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行政院國家科學委員會專題研究計畫 成果報告

破裂介質中的熱傳導方程式

研究成果報告(精簡版)

計 畫 類 別 : 個別型

計 畫 編 號 : NSC 98-2115-M-009-011-

執 行 期 間 : 98 年 08 月 01 日至 99 年 07 月 31 日

執 行 單 位 : 國立交通大學應用數學系(所)

計 畫 主 持 人 : 葉立明

報 告 附 件 : 出席國際會議研究心得報告及發表論文

處 理 方 式 : 本計畫可公開查詢

中 華 民 國 99 年 10 月 29 日

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背景及目的

很多的化學工廠的廢水經由水井排放到地底,地面的有毒廢棄物也經由雨水進入地底,核能電

廠儲存在地底下的核廢棄物由於時間的關係造成容器腐蝕、或是由於地層變動造成容器破裂,放射

性物質也因此進入地下水。這些都造成日常飲用水的不安全。這些問題不是只發生在臺灣,世界其

它國家也有同樣的情形。歐美一些國家都有專責機構負責這些污染源的清除工作。身體內的血液在

血管中流動的問題,地底下的碳氫化合物的抽取等以上都屬於多相流問題[6,10,12,40]。因此,了

解多孔介質中的多相流的變化對解決很多實際問題是重要的。

這是個一年期的計劃。我們計劃探討熱傳導在破裂多孔介質中的宏觀模式。地底下的縫隙結

構與地質性質是十分複雜的,然而流體在地底下的運動卻與它們息息相關,譬如流體運動的方向、

快慢、time-scale 等[17,18,19,20,21,25,26, 27,30, 31,33]。破裂多孔介質是一種特殊的地質

結構,在這種介質中流體的運動往往呈現出兩種不同的 time scale 的現象。污染源擴散時平流與

對流現象則常發生在污染源的附近或較遠處。熱傳導現象(一種 transport equation)則對應到地

下污染源在地底擴散時的平流與對流問題。熱傳導在破裂多孔介質中自然也有流速快慢不同的區

域。描述多孔介質中的可混合與不可混合流體的運動方程式都包含有 transport equation。換言

之,了解熱傳導現象在破裂多孔介質中的的數學模式是要進一步了解污染源在地底擴散情形的基

礎。

探討在破裂多孔介質中的多相流的問題不是一個新的問題。但到目前為止討論的方式主要

仍是數值模擬加上一些平均的方法,數值模擬的缺點是需要很多的計算時間且是 case by case

的討論。至於用數學分析的討論方式則是最近才開始。數學文獻中關於破裂多孔介質中的多相流

的問題大多只單討論 flow equation[51,52]的部份。之前我們的計劃也討論 flow equation (一

種橢圓形方程式) 在破裂多孔介質中的情形。我們希望借助之前的經驗來幫助了解 transport

equation

在破裂多孔介質中的情形。底下是我們考慮的抛物線微分方程式。

3

is a domain and

 =

 ∪

f

m

. Denote absolute permeability by

K in

f

and

k in

m

, phase pressure by

P in

 and

f

p

in

m

, and external source by

F

Q ,

in

 and

f

q ,

f

in

m

. The equations are

K

P

Q

F

P

t

(

)

in

f

( T

0

,

)

,

k

p

q

f

p

t

(

)

in

m

( T

0

,

)

 

P

Q

n

k

p

q

n

K

)

(

)

(

on

m

( T

0

,

)

,

p

P

on

m

( T

0

,

)

P

P

in

f

(3)

0

p

p

in

m

with periodic boundary condition on

.我們想考慮當

變動時,

P 的何種 norm 與

的變化無關?

除了抛物線微分方程式,我們也考慮橢圓形方程式在 perforated domain 的數值近似解

的誤差估計問題。

研究方法、進行步驟及執行進度。

這是一個抛物線微分方程式,我們以底下的方式進行: 一. 利用半群理論(semigroup

theory) 我們得到時間方面的解的均勻 Holder norm 的估計。 二.利用 three-step

compactness method 我們得到空間方面的解的均勻 Holder norm 的估計。三.為了估計不

連續截面的變化,我們用到 pseudodifferential operator [40]及 boundary integral

method[14]。在函數空間方面則利用 Besov space and Holder space [2,37,41]。由於考

慮的抛物線微分方程式是在破裂多孔介質中,介質基本上是不連續的,因此在空間方面的

解的 Holder norm 只在局部較平滑的區域得到,在不平滑的區域則沒有均勻 Holder norm 的

估計。

關於橢圓形方程式,我們則利用 three-step compactness method 與 Taylor

expansion 得到 數值近似解的誤差估計。

(四)成果與自評。

一、得到不均勻抛物線微分方程式的解的 Holder norm 的均勻估計結果[58]。有了此結

再利用 two-scale method 我們可以很容易的導出熱傳導在破裂多孔介質中的宏觀模

式。

二、得到橢圓形方程式在 perforated domain 的數值近似解的誤差估計[59]。

References

[1] E. Acerbi, V. Chiado Piat, G. Dal Maso, and D. Percivale

An extension theorem from

connected sets, and homogenization in general periodic domains.

Nonlinear Analysis,

18 (1992) 481-496.

[2] R. A. Adams Sobolev Spaces.

Academic Press, 1975.

[3] Gregoire Allaire

Homogenization and two-scale convergence.

SIAM I. Math. Anal.,

23 (1992) 1482-1518.

(4)

porous media.

Annali Scu. norm. sup. Pisa Cl. Sci. 12(4) (1985) 335-392.

[5] H. W. Alt and S. Luckhaus Quasilinear elliptic--parabolic differential equations.

Math. Z. 183 (1983) 311-341.

[6] S.N. Antontsev, A. V. Kazhikhov, and V.N. Monakhov

Boundary Value Problems in

Mechanics in Nonhomogeneous Fluids. Elsevier, {1990}.

[7] T. Arbogast

The existence of weak solutions to single porosity and simple

dual-porosity models of two-phase incompressible flow.

Nonlinear Analysis 19(11)

(1992) 1009-1031.

[8] T. Arbogast, J. Douglas, and U. Hornung

Derivation of the double porosity model of

single phase flow via homogenization theory,

SIAM J. Math. Anal., 21 (1990) 823-836.

[9] T. Arbogast, J. Douglas, and P. J. Paes~Leme Two models for the waterflooding of

naturally fractured reservoirs.

Proceedings, Tenth SPE Symposium on Reservoir

Simulation, SPE 18425, Society of Petroleum Engineers, Dallas, Texas (1989).

[10] Bear J., Buchlin J.M.

Modelling and Applications of Transpot Phenomena in Porous

Media. Kluwer Academic Publishers, Boston, London, 1991.

[11] Alain Bourgeat, Stephan Luckhaus, and Andro Mikelic

Convergence of the

homogenization process for a double-porosity model of immiscible two--phase flow.

SIAM J. Math. Anal. 27(6) (1996) 1520--1543.

[12] Chavent G., Jaffr'e J.

Mathematical Models and Finite Elements for Reservoir

Simulation. North-Holland, Amsterdam, 1986.

[13] Z. Chen Degenerate two-phase incompressible flow 1. existence, uniqueness and

regularity of a weak solution.

Journal of Differential Equations 171 (2001) 203-232.

[14] G. Chen, J. Zhou

Boundary Element Methods . Academic Press, 1992.

[15] G. W. Clark, R.E. Showalter Two-scale convergence of a model for flow in a partially

fissured medium,

Electronic Journal of Differential Equations, 1999(2) (1999) 1-20.

[16] E. DiBenedetto

Degenerate Parabolic Equations. Springer-Verlag, 1993.

[17] J. Jr. Douglas, J. L. Hensley, and T. Arbogast

A dual--porosity model for

waterflooding in naturally fractured reservoirs.

Computer Methods in Applied

(5)

Mechanics and Engineering 87 (1991) 157-174.

[18] Douglas J. Jr., Hensley J. L., Arbogast T., Paes~Leme P. J., Nunes N. P.Medium and

tall block models for immiscible displacement in naturally fractured reservoirs. To

appear in the Proceedings of the Symposium on Numerical Analysis,

Polytechnical

University of Madrid, May 1990.

[19] Jim Douglas Jr., Frederico Furtado, Felipe Pereira, L.M. Yeh Numerical Methods for

Transport-Dominated Flows inHeterogeneous Porous Media.

Computational Methods in

Water Resources XII, 1, 469-476, 1998.

[20] Douglas J. Jr., Pereira F., Yeh L. M. A parallelizable characteristic scheme for two

phase flow 1: single porosity models.

Computational and Applied Mathematics, 14, no

1, 1995.

[21] Jim Douglas Jr., Felipe Pereira, L.M. Yeh

A parallel method for two-phase flows in

naturally fractured reservoirs.

Computational Geosciences, 1 no. 3-4, 333—368, 1997.

[22] Jim Douglas Jr., Felipe Pereira, L.M. Yeh A Locally Conservative Eulerian-Lagrangian

Numerical Method and its Application to Nonlinear Transport in Porous Media.

Computational Geosciences, 4 no. 1, 1--40, 2000.

[23] Jim Douglas Jr., Felipe Pereira, L.M. Yeh A Locally Conservative Eulerian-Lagrangian

Method for Flow in a Porous Medium of a Mixture of Two Components Having

Different Densities.

Numerical Treatment of Multiphase Flows in Porous Media

(Zhangxin Chen, Richard E. Ewing, and Z.-C. Shi ed.), Lecture Notes in Physics, 552,

138--155, 2000.

[24] Cesar Almeida,Jim Douglas Jr., Felipe Pereira, L.C. Roman, L. M. Yeh

Algorithmic

Aspects of a Locally Conservative Eulerian-Lagrangian Method for Transport-dominated

Diffusion System.

Fluid Flow and Transport in Porous Media: Mathematical and

Numerical Treatment, Contemporary Mathematics, 295, 37-48, 2002.

[25] Douglas J. Jr., Pereira F., Yeh L. M., Paes Leme P. J. A massively parallel iterative

numerical algorithm for immiscible flow in naturally fractured reservoirs,

volume 114

of International Series of Numerical Mathematics (J. Douglas, Jr., and U. Hornung,

eds.). 1993.

[26] Douglas J. Jr., Pereira F., Yeh L. M., Paes Leme P. J. Domain decomposition for

immiscible displacement in single porosity systems,

volume 164 of Lecture Notes in

Pure and Applied Mathematics (M. Krizek, P. Neittaanmaki, and R. Stenberg, eds.). 1994.

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[27] Douglas J. Jr.,Hensley J. L.,Yeh L. M.et-al. A derivation for Darcy's Law for miscible

fluid and a revised model for miscible displacement in porous media.

Computational

Methods in Water Resources, 1X, Vol.2, 1992.

[28] Fabrie P., Langlais M. Mathematical analysis of miscible displacement in porous media.

SIAM I. Math. Analy., 23 no. 6, 1992.

[29] Gilbarg D., Trudinger N. S.

Elliptic Partial Differential Equations of Second Order.

Springer-Verlag, Berlin, second edition, 1983.

[30] James R. Gilman and Hossein Kazemi Improvements in simulation of naturally fractured

reservoirs.

Soc. Petroleum Engr. J. 23 (1983) 695--707.

[31] Glimm J., Lindquist B., Pereira F., Peierls R. The fractal hypothesis and anomalous

diffusion.

Matem\'atica Aplicada e Computacional, 11, 1992.

[32] Jianguo Huang, Jun Zhou. Some new a priori estimates for second order elliptic and

parabolic interface problems,

Journal of Differential Equations, 184 (2002) 570--586.

[33] H. Kazemi,

L.S. Merrill, Jr., K.L. Porterfield, and P.R. Zeman. Numerical simulation

of water-oil flow in naturally fractured reservoirs.

Soc. Petroleum Engr. J. (1976)

317--326.

[34] D. Kroener and S. Luckhaus. Flow of oil and water in a porous medium.

J. diff. Eqns.

55 (1984) 276--288.

[35] O. A. Ladyzenskaja, V.A. Solonnikov, N.N. Ural'tzeva.

Linear and Quasilinear

Equations of Parabolic Type. Transl. Math. Mono. Vol.23 AMS, Providence, RI, 1968.

[36] Yan Yan Li, Michael Vogelius. Gradient estimates for solutions to divergence form

elliptic equations with discontinuous coefficients,

Arch. Rational Mech. Anal.,

153(2000) 91--151.

[37] S. M. Nikol'skii.

Approximation of Functions of Several Variables and Imbedding

Theorems. Springer-Verlag, Berlin, 1975.

[38] Nochetto R. H. Error estimate for multidimensional sigular parabolic problems.

Japan

J. Appl. Math., 4, 1987.

[39] Peaceman D. W.

Fundamentals of Numerical Reservoir Simulation. Elsevier, New York,

(7)

[40] Michael E. Taylor.

Psudodifferential Operators. Princeton University, 1981.

[41] Hans Triebel.

Interpolation Theory, Function Spaces, Differential Operators. North

Holland, 1978.

[42] L. M. Yeh. Convergence of A Dual--Porosity Model for Two--phase Flow in Fractured

Reservoirs.

Mathematical Methods in Applied Science, 23, 777--802, 2000.

[43] Douglas J. Jr., Pereira F.,L. M. Yeh. Relations between phase mobilities and capillary

pressures of two--phase flows in fractured media.

Fluid Flow and Transport in Porous

Media: Mathematical and Numerical Treatment, Contemporary Mathematics, 295, 159--171,

2002.

[44] L. M. Yeh. On two-phase flows in fractured media.

Mathematical Models and Methods

in Applied Science, 12, No. 8, 1075--1107, 2002.

[45] L. M. Yeh. Homogenization of two-phase flows in fractured media.

Mathematical Models

and Methods in Applied Science, 11(16) 2006.

[46] L. M. Yeh. Holder continuity for two-phase flows in porous media.

Mathematical Methods

in Applied Science, 2006.

[47] L. M. Yeh. A moderate-sized block model for two-phase flows in fractured porous media.

submitted.

[48] Jim Douglas, L.M. Yeh. Two-component miscible displacement in fractured media.

submitted.

[49] L.M. Yeh. Tall block models for two-phase flows in fractured

porous media.

submitted.

[50] Robert Burridge, Joseph B. Keller. Poroelasticity equations derived from

microstructure, J. Accoust. Soc. Am. 70(4) 1140-1146, 1981.

[51] Jacob Rubinstein, S. Torquato. Flow in random porous media: mathematical formulation,

variational principles, and rigorous bounds. J. Fluid Mech. 206, 25-46, 1989.

[52] A. Yu. Beliaev, S.M. Kozlov, Darcy equation for random porous media, Comm. Pure App.

Math. XLIX 1-34, 1996

[53] V.V. Jikov, S.M. Kozlov, O.A. Oleinik, Homogenization of differential operators and

integral functionals, Springer-Verlag, 1991.

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[54] L.M. Yeh. A tall block model for miscible displacement in fractured media. preprint.

[55] L.M. Yeh. Elliptic equations in highly heterogeneous porous media. conditionally

accept.

[56] L.M. Yeh. A priori estimate for non-uniform elliptic equations. preprint.

[57] L.M. Yeh. Uniform

p

L

estimate for elliptic equations in perforated domains.

preprint.

[58] L.M. Yeh. H\"older estimate for non-uniform parabolic equations in highly

heterogeneous media. preprint.

[59] L.M. Yeh. Pointwise error estimate for elliptic equations in perforated domains.

preprint.

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October 28, 2010

H¨older estimate for non-uniform parabolic equations in highly heterogeneous media

Li-Ming Yeh

Department of Applied Mathematics

National Chiao Tung University, Hsinchu, 30050, Taiwan, R.O.C. [email protected]

Uniform bound for the solutions of non-uniform parabolic equations in highly heteroge-neous media is concerned. The space domains are periodic as well as consist of a con-nected high permeability sub-region and a disconcon-nected matrix block sub-region with low permeability. Let ǫ denote the size ratio of matrix blocks to the whole domain and let the permeability ratio of the matrix block sub-region to the connected high permeability sub-region be of the order ǫ2. It is proved that the H¨older norm of the non-uniform

parabolic solutions in connected sub-region is bounded uniformly in ǫ.

Keywords: Highly heterogeneous media, pseudo-differential operator, paramatrix, strict solution, infinitesimal generator, numerical range.

AMS Subject Classification: 35K10, 35K20, 35M13

1. Introduction

Uniform H¨older estimate for the solutions of non-uniform parabolic equations in highly heterogeneous media is presented. The equations have many applications in multiphase flows in porous media, the stress in composite materials, and so on (see [3, 12, 17] and references therein). The domain Ω ⊂ Rn(n ≥ 2) has boundary ∂Ω as

well as contains a connected high permeability sub-region and a disconnected matrix block sub-region with low permeability. Let Y ≡ [0, 1]nbe a cell consisting of a

sub-domain Ymcompletely surrounded by another connected sub-domain Yf(≡ Y \Ym),

ǫ ∈ (0, 1), and Ω(2ǫ) ≡ {x ∈ Ω : dist(x, ∂Ω) > 2ǫ}. The disconnected sub-region is Ωǫ

m ≡ {x : x ∈ ǫ(Ym+ j) ⊂ Ω(2ǫ) for j ∈ Zn}, the connected sub-region is

Ωǫ

f ≡ Ω \ Ωǫm, and the boundary of Ωǫm is represented by ∂Ωǫm. The non-uniform

parabolic equations in [0, T ] × Ω are        ∂tUǫ− ∇ · (Λǫ∇Uǫ) = Fǫ in (0, T ] × Ω, Uǫ= 0 on (0, T ] × ∂Ω, Uǫ= Uǫ,0 in {0} × Ω, (1.1) where Λǫ ≡ ( Kǫ in Ωǫf, ǫ2k ǫ in Ωǫm,

and Kǫ and kǫ are positive smooth functions in Ω.

Since ǫ ∈ (0, 1), equations (1.1) are non-uniform parabolic equations with

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October 28, 2010

2 H¨older estimate

tinuous coefficients. In [20], existence of solution in W2,1

p ([0, T ]×Ω) space for uniform

parabolic equations with discontinuous coefficients can be found. For non-uniform parabolic equations with smooth coefficients, existence of solution in C2,α([0, T ]×Ω)

space was studied in [13]. It is also known that if Fǫ, Uǫ,0 are smooth, a piecewise

regular solution of (1.1) exists uniquely for each ǫ and, by energy method, the H1

norm of the parabolic solution in the connected high permeability sub-region is bounded uniformly in ǫ [12, 16]. Many studies of the uniform estimate in ǫ for the elliptic equations in highly heterogeneous media had been done [4, 12, 15, 17, 19, 23], but little for parabolic equations. Existence of piecewise regular solutions for elliptic diffraction equations in Hilbert space was considered in [12, 15]. Uniform Lipschitz estimate in ǫ for Laplace equation in perforated domains was given in [23], and uniform Lpestimate in ǫ of the same problem was considered in [19].

Lip-schitz estimate for uniform elliptic equations was studied in [17]. Uniform H¨older and Lipschitz estimates in ǫ for uniform elliptic equations in periodic domains were obtained in [4]. This work is to present uniform H¨older estimate in ǫ for the solutions of the non-uniform parabolic equations with discontinuous coefficients. Permeabil-ity fields (that is, Λǫ) are not periodic and are allowed to have large deviation. It is

proved that the H¨older norm of the non-uniform parabolic solutions in connected sub-region is bounded uniformly in ǫ.

2. Notation and main result

Let Lp (resp.Hk, Wk,p) denote complex Sobolev space with norm k · k

Lp (resp.

k · kHk,k · kWk,p), C0∞ be the set containing all infinite differentiable functions with

compact support, and Cσ (resp. C1,σ) denote H¨older space with norm k · k

Cσ (resp.

k · kC1,σ) for σ ∈ (0, 1], k ≥ −1, and p ∈ [1, ∞] [11]. [ϕ]Cσ (resp. [ϕ]C1,σ) denotes

the H¨older semi-norms of ϕ (resp. ∇ϕ). If ϕ is a complex function, ϕ denotes its complex conjugate. If B1and B2are two Banach spaces, L(B1, B2) is the set of all

bounded linear maps from B1to B2with norm k · kL(B1,B2). For any Banach space

B, define kϕ1, ϕ2, · · · , ϕmkB≡ kϕ1kB+ kϕ2kB+ · · ·+ kϕmkB, denote its dual space

by B′

, and denote the pairing between B and its dual space B′

by h·, ·iB,B′. The

function spaces L∞

(I; B), C(I; B), Cσ(I; B) for σ ∈ (0, 1] and an interval I ⊂ R are

defined as those in [18]. Br(x) represents a ball centered at x with radius r. For any

domain D, D is the closure of D, D/r ≡ {x : rx ∈ D}, |D| is the volume of D, and XDis the characteristic function on D. For any ϕ ∈ L1(B

r(x) ∩ Ω), we define (ϕ)x,r≡ − Z Br(x)∩Ω ϕ(y)dy ≡ 1 |Br(x) ∩ Ω| Z Br(x)∩Ω ϕ(y)dy. For any p ∈ (1, ∞) and ǫ > 0, we define

       Aǫϕ ≡ −∇ · (Λ ǫ∇ϕ), Bp(Aǫ) ≡ϕ ∈ W01,p(Ω) : ϕ ∈ W2,p(Ωǫf) ∪ W2,p(Ωǫm), Kǫ∇ϕ · ~nǫ|∂Ωǫ m = ǫ 2k ǫ∇ϕ · ~nǫ|∂Ωǫ m ,

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October 28, 2010

H¨older estimate 3

where ~nǫis a normal vector on ∂Ωǫ

m. Bp(Aǫ) with norm kϕkBp(Aǫ)≡ kA

ǫϕk Lp(Ω)is

a normed space. M(α, β; D) ≡ {ϕ : D → R|ϕ ∈ L∞

(D), 0 < α ≤ ϕ ≤ β}. For any σ ∈ (0, 1) and δ, α, β > 0, we assume

A1. Ω and Ymare smooth domains,

A2. Kǫ, kǫ∈ M(α, β; Ω) and

kKǫ(ǫx) − αǫ,jkW1,∞((Y

f+j)∩Ω/ǫ)+ kkǫ(ǫx) − αǫ,jkW1,∞((Ym+j)∩Ω/ǫ)≤ cαǫ,j

where j ∈ Zn, α

ǫ,j depend on ǫ, j, and c is small and depending on Yf,

A3. Fǫ ∈ Cσ([0, T ]; Ln+δ(Ω)), −AǫUǫ,0+ Fǫ(0, x) ∈ Bn+δ(−Aǫ), and Uǫ,0 ∈

Bn+δ(−Aǫ).

The main result is:

Theorem 2.1. Under A1-A3, the solution of (1.1) satisfies kUǫkC1([0,T ];Ln+δ(Ω))+ kUǫkC([0,T ];Cµ(Ωǫ f))+ sup j∈Zn ǫ(Ym +j)⊂Ωǫm ǫkUǫkC([0,T ];Cµ(ǫ(Ym+j))) ≤ c kUǫ,0kBn+δ(Aǫ)+ kFǫkCσ([0,T ];Ln+δ(Ω)), (2.1)

where δ > 0, µ, σ ∈ (0, 1), µ is a constant depending on n, δ, α, β, Yf, Ω, and c is a

constant independent of ǫ. Moreover, there is a ν ∈ (0, µ) such that kUǫkCν([0,T ]×Ωǫ

f)≤ c kUǫ,0kBn+δ(Aǫ)+ kFǫkCσ([0,T ];Ln+δ(Ω)), (2.2)

where c is a constant independent of ǫ.

References

1. E. Acerbi, V. Chiado Piat, G. Dal Maso, and D. Percivale, An extension theorem from connected sets, and homogenization in general periodic domains, Nonlinear Analysis 18 (1992) 481–496.

2. R. A. Adams, Sobolev Spaces (second edition, Academic Press, 2003).

3. Gregoire Allaire, Homogenization and two-scale convergence, SIAM I. Math. Anal. 23 (1992) 1482–1518.

4. Marco Avellaneda, Fang-Hua Lin, Compactness methods in the theory of homogeniza-tion, Communications on Pure and Applied Mathematics Vol. XI (1987) 803–847. 5. M. Briane, A. Damlamian, P. Donato, H-convergence for perforated domains,

Non-linear partial differential equations and their applications. College de France Seminar, Vol. XIII (Paris, 1994/1996), Pitman Research Notes in Mathematics Series 391 (1998) 62–100.

6. G. Chen and J. Zhou, Boundary Element Methods (Academic Press, 1992). 7. Doina Cioranescu and Patrizia Donato, An Introduction to Homogenization

(Oxford, 1999).

8. John B. Conway, A course in functional analysis, (Springer-Verlag, 1985). 9. L. Escauriaza, E.B. Fabes, G. Verchota, On a regularity theorem for weak solutions to

transmission problems with internal Lipschitz boundaries, Proceedings of the American Mathematical Society 115(4) (1992) 1069–1076.

10. M. Giaquinta, Multiple integrals in the calculus of variations, (Study 105, Annals of Math. Studies, Princeton Univ. Press., 1983).

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October 28, 2010

4 H¨older estimate

11. D. Gilbarg, N. S. Trudinger Elliptic Partial Differential Equations of Second Order. Springer-Verlag, Berlin, second edition, 1983.

12. Jianguo Huang, Jun Zou, Some new a priori estimates for second-order elliptic and parabolic interface problems, Journal of Differential Equations 184 (2002) 570–586. 13. A. V. Ivanov, Quasilinear degenerate and nonuniformly elliptic and parabolic

equations of second order , American Mathematical Society, Providence, RI, 1984. 14. V.V. Jikov, S.M. Kozlov, O.A. Oleinik, Homogenization of Differential

Opera-tors and Integral Functions, (Springer-Verlag, 1994).

15. O. A. Ladyzhenskaya, Nina N. Ural’tseva Elliptic and Quasilinear Elliptic Equations. Academic Press, 1968.

16. O. A. Ladyzenskaja, V. A. Solonnikov, N. N. Ural’ceva Linear and Quasi-linear Equa-tions of Parabolic Type . Providence, RI : American Mathematical Society, 1968. 17. Yan Yan Li, Michael Vogelius, Gradient estimates for solutions to divergence form

el-liptic equations with discontinuous coefficients, Arch. Rational Mech. Anal. 153 (2000) 91–151.

18. Alessandra Lunardi, Analytic semigroups and optimal regularity in parabolic problems (Basel : Birkhauser, 1995).

19. Nader Masmoudi, Some uniform elliptic estimates in porous media, C. R. Acad. Sci. Paris Ser. I 339 (2004) 849–854.

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differ-entical equations (New York : Springer-Verlag, 1983).

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October 28, 2010

Pointwise error estimate for elliptic equations in perforated domains

Li-Ming Yeh

Department of Applied Mathematics

National Chiao Tung University, Hsinchu, 30050, Taiwan, R.O.C. [email protected]

Numerical approximation for the solutions of elliptic equations in perforated domains is concerned. Let ǫ denote the size ratio of the holes of some perforated domains to their whole domains. As ǫ closes to 0, the elliptic solutions in perforated domains approach a solution of some homogenized equation. So it is expected that the numerical approxima-tion of the soluapproxima-tion of the homogenized equaapproxima-tion is a good approximaapproxima-tion for the elliptic solutions in perforated domains when ǫ is small. In this work, the L∞

estimate and the Lipschitz estimate for the difference between the elliptic solutions in perforated domains and the numerical approximation of the homogenized solution are derived. Higher order estimate in Lipschitz norm for the difference between the elliptic solutions in perforated domains and the homogenized solution is also derived.

Keywords: elliptic solution, perforated domain, homogenized solution.

AMS Subject Classification: 65N12, 65N15, 65N22

1. Introduction

Pointwise error estimate for the numerical approximation of the solutions of elliptic equations in perforated domains is presented. Let Ω ⊂ Rn (n = 2 or 3) be a smooth

domain with boundary ∂Ω, Y ≡ [0, 1]n consist of a sub-domain Y

m completely

surrounded by another connected sub-domain Yf (≡ Y \ Ym), ǫ ∈ (0, 1), Ω(2ǫ) ≡

{x ∈ Ω : dist(x, ∂Ω) > 2ǫ}, Ωǫm ≡ {x : x ∈ ǫ(Ym+ j) ⊂ Ω(2ǫ) for j ∈ Zn} with

boundary ∂Ωǫ

m, and Ωǫf ≡ Ω \ Ωǫm be a connected region. The equations in the

perforated domain Ωǫ f are        −∇ · (Kǫ∇Uǫ) + λUǫ= F in Ωǫf, Kǫ∇Uǫ· ~nǫ= 0 on ∂Ωǫm, Uǫ= 0 on ∂Ω, (1.1)

where λ ≥ 0, Kǫ(x) = K(xǫ), K is a positive periodic function in Rn with period

Y , and ~nǫ is the unit normal vector on ∂Ωǫ

m. When ǫ is small, direct numerical

simulation of the solution of (1.1) can be very expensive. It is known that if F ∈ L2(Ω), the H1 solution of (1.1) exists uniquely and satisfies

kUǫkH1(Ωǫ

f)≤ ckF kL2(Ω),

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2 Error estimate

where c is a constant independent of ǫ [9]. By compactness principle [2], there exists a function U ∈ H1(Ω) such that the solution Uǫof (1.1) satisfies

Kǫ∇UǫXΩǫ f → K

∇U in L2(Ω) weakly as ǫ → 0, (1.2)

where XΩǫ

f is the characteristic function on Ω

ǫ fand K

is a constant positive definite matrix depending on K, Yf (explicit form of K∗is in (2.2) below). The function U

in (1.2) satisfies (

−∇ · (K∗

∇U ) + λ|Yf|U = |Yf|F in Ω,

U = 0 on ∂Ω, (1.3) where |Yf| is the volume of Yf. Therefore, it is expected that the numerical

approx-imation for the solution of (1.3) is a good approxapprox-imation for the solution of (1.1), especially when ǫ is small. The error estimate between the numerical solution and the analytic solution of (1.3) had been extensively studied (see [4, 7, 10, 15] to name a few). So we shall focus on the error estimate for the solutions of (1.1) and (1.3).

By homogenization theory, solutions of elliptic equations in periodic domains in general converge to a solution of some homogenized elliptic equation with con-vergence rate ǫ in L2 norm and with convergence rateǫ in H1 norm as ǫ closes

to 0 (see [3, 11, 14] and references therein). In [5, 13], higher order asymptotic expansion for the solutions of elliptic equations in perforated domains was given. Higher order convergence rate for the solution of (1.1) for λ = 0 case was derived in Hilbert spaces [3, 6, 14]. Different from the literatures mentioned above in which L2 space was considered, we present pointwise error estimate for the solutions of

(1.1) and (1.3) for λ ≥ 0. More precisely, the L∞

error estimate with convergence rate ǫ for the solutions of (1.1) and (1.3) is proved. For equation (1.1) with λ > 0 and with periodic boundary condition case, W1,∞ error estimate with convergence

rate ǫ is also derived. In particular, for equation (1.1) with λ = 0 and with periodic boundary condition case, higher order approximation in Lipschitz norm is obtained as well.

2. Notation and main results

Denote by Ck,α the H¨older space with norm k · k

Ck,α, by [g]Ck,α the H¨older

semi-norm of g, and by Lp (resp. Hs, Ws,p) the Sobolev space with norm k · k

Lp (resp.

k · kHs, k · kWs,p) for k ≥ 0, α ∈ [0, 1], s ≥ 1, and p ∈ [1, ∞] (see [9]). For any

Banach space B, we define kg1, g2, · · · , gkkB≡ kg1kB+ kg2kB+ · · · + kgkkB. Br(x)

is a ball centered at x with radius r. For any domain D, D is the closure of D, D/r ≡ {x : rx ∈ D}, |D| is the volume of D, and XD is the characteristic function

on D. For any g ∈ L1(Ω), (g)x,r≡ − Z Br(x)∩Ω g(y)dy ≡ 1 |Br(x) ∩ Ω| Z Br(x)∩Ω g(y)dy.

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October 28, 2010

Error estimate 3

Define Zm≡ ∪j∈Zn(Ym+ j) with boundary ∂Zm, Zf ≡ Rn\ Zm, Zmǫ ≡ ǫZm with

boundary ∂Zmǫ , and Zfǫ≡ Rn\ Zmǫ . For D ∈ {Rn, Zf, Zfǫ}, we define

Wpers,p(D) ≡ {g ∈ Wlocs,p(D) : g is a periodic function in D with period [0, 1]n}

with norm kgkWpers,p(D) ≡ kgkWs,p(D∩Y ) for s ≥ 1 and p ∈ [1, ∞]. Similar definition

for Lpper(D), Hpers (D), Cperk,α(D) when D ∈ {Rn, Zf, Zfǫ}, k ≥ 0, α ∈ [0, 1], s ≥ 1,

and p ∈ [1, ∞]. If G(x) = g(ǫx), g ∈ C0,α

per(Zfǫ) for α ∈ (0, 1), define |||g|||C0,αper(Zfǫ) ≡

kGkC0,α(Z f).

For each i = 1, · · · , n, we find X(i)(y) ∈ H1

per(Zf) satisfying, in cell Yf,

       −∇ · (K(∇X(i)+ ~e i)) = 0 in Yf, K(∇X(i)+ ~e i) · ~ny = 0 on ∂Ym, R YfX (i)dy = 0, (2.1)

where ~ny denotes the unit normal vector on ∂Ymand ~ei is a unit vector in the i-th

coordinate direction for i = 1, · · · , n. For any ν > 0, we define X(i)ν (x) ≡ νX(i)(xν),

X ≡ (X(1), · · · , X(n)), and Xν ≡ (X(1)ν , · · · , X(n)ν ). Denote by Ξ a n × n matrix

function whose (i, j) component is ∂yiX

(j) and define

K∗≡ Z

Yf

K(y)(I + Ξ(y))dy, (2.2) where I is the identity matrix. By [2] and remark in page 90 [11], K∗

is a constant symmetric positive definite matrix. For i1, i2= 1, · · · , n, find X(i1,i2)(y) ∈ Hper1 (Zf)

satisfying, in cell Yf,        ∇ · (K∇X(i1,i2)) + ∂ i1(KX (i2)) = −K(δ i1,i2+ ∂i1X (i2)) +K ∗ i1,i2 |Yf| in Yf, K(∇X(i1,i2)· ~n y+ X(i2)nyi1) = 0 on ∂Ym, R YfX (i1,i2)dy = 0. (2.3) Here δi1,i2 ≡ ( 1 if i1= i2, 0 if i16= i2, K∗ i1,i2 is the (i1, i2) component of K ∗ in (2.2), and nyi1 is the i1 component of ~ny. Similarly define X(i1,i2,...,iℓ)∈ Hper1 (Zf) for ℓ ≥ 3,

ij ∈ {1, · · · , n}, and j ∈ {1, 2, · · · , ℓ} as, in cell Yf,

           ∇ · (K∇X(i1,...,iℓ)) + ∂ i1(KX (i2,...,iℓ)) = −K(δi1,i2X (i3,...,iℓ)+ ∂ i1X (i2,...,iℓ)) in Y f, K ∇X(i1,...,iℓ)· ~n y+ X(i2,...,iℓ)nyi1 = 0 on ∂Ym, R YfX (i1,...,iℓ)dy = 0. (2.4)

By energy method and Lax-Milgram theorem [9], X(i1,...,iℓ)for ℓ ≥ 1 in (2.1), (2.3),

and (2.4) are solvable uniquely. By Lemma 6.29 [9], if K ∈ C1,α

per(Zf) for α ∈ (0, 1),

then

kX(i1,...,iℓ)k

C2,α(Z

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4 Error estimate

2.1. L∞

error estimate We shall assume

A1. Ω and Ym are bounded C1,α domains,

A2. K ∈ C1,α

per(Zf) is a positive function,

A3. F ∈ W1,n+δ(Ω),

where α ∈ (µ, 1), µ ≡ n+δδ , n ∈ {2, 3}, and δ ∈ (0, 3). We recall an extension result in [1].

Lemma 2.1. For 1 ≤ p < ∞, there is a constant c(Yf, p) and a linear continuous

extension operator Πǫ: W1,p(Ωǫf) → W1,p(Ω) such that (1) If ϕ ∈ W1,p(Ωǫf), then

                 Πǫϕ = ϕ in Ωǫf almost everywhere, kΠǫϕkLp(Ω)≤ c(Yf, p)kϕkLp(Ωǫ f), k∇ΠǫϕkLp(Ω)≤ c(Yf, p)k∇ϕkLp(Ωǫ f), kΠǫϕkL∞(Ω)≤ c(Yf, p)kϕkL(Ωǫ f) if ϕ ∈ L ∞ (Ωǫ f), Πǫϕ = ζ in Ω if ϕ = ζ|Ωǫ

f for some linear function ζ in Ω.

(2) If ζ(x) ≡ ϕ(rx) in B1(z) ∩ Ωǫf/r for any z ∈ Rn and any constant r > ǫ, there

is a θ ∈ (0, 1) so that Πǫ/rζ(x) = (Πǫϕ)(rx) in Bθ(z) ∩ Ω/r

Lemma 2.1 also holds if Ωǫ

f (resp. Ω) is replaced by Zfǫ (resp. Rn). For the

solutions of (1.1) and (1.3), we have the following error estimate:

Lemma 2.2. Under A1–A3, there is a constant ǫ0 such that the solutions of (1.1)

and (1.3) satisfy, for any ǫ ∈ (0, 1) and λ ∈ [0, ǫ0),

kUǫ− U kL∞(Ωǫ

f)≤ cǫkF kW1,n+δ(Ω),

where c is a constant independent of ǫ, λ.

We now describe the families of subspaces to be used to approximate the solution of (1.3). Let {Fh : 0 < h ≤ 1} be a family of subdivisions of Ω into disjoint,

non-empty, connected, open sets τ ∈ Fh of diameter not greater than h (a subdivision

means Ω = ∪τ ∈Fhτ ). Then we assume

A4. {Fh: 0 < h ≤ 1} is a quasi-uniform (see page 5 [10]) family of subdivisions

of Ω and {Sh : 0 < h ≤ 1} is a family of linear spaces of functions on Ω

such that, for each ϕ ∈ Sh and τ ∈ Fh, we have ϕ|

τ ∈ P, where P is a

fixed finite dimensional space of polynomials independent of h, τ , and ϕ. A5. For some non-negative integer m not greater than n and for some integer

k greater than m, there is a linear mapping Jhfor each h ∈ (0, 1] of

Dh≡ {ζ ∈ Cm(Ω) : ζ|∂Ω= 0} ∪ {ζϕ : ζ ∈ Cm(Ω), ϕ ∈ Sh}

into Sh such that

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Error estimate 5

Furthermore, for any integer ℓ and any p ∈ [1, ∞] such that        max{1, m} + n ≤ ℓ ≤ k if p = 1, max{1, m} + n/p < ℓ ≤ k if 1 < p < ∞, m < ℓ ≤ k if p = ∞, it follows that (ii) 1 P j=0 hj+n/pkDj(ζ − Jhζ)k L∞(τ )≤ cℓ,phℓkζkWℓ,p(τ )

for all τ ∈ Fh and ζ ∈ Dh∩ Wℓ,p(τ ), where c

ℓ,pis independent of ζ, τ, h.

A6. For all h ∈ (0, 1], Sh⊂ W1,∞(Ω).

Many finite element spaces satisfying A4–A6 have been constructed, see [7, 10] and references therein. Inverse inequalities (see Theorem 3.2.6 [7]) hold in these finite element spaces. Define a bilinear form Lh

γ on Sh× Sh as Lh γ(ϕ, ζ) ≡ Z Ω K∗∇ϕ∇ζ dx + Z Ω λ|Yf|ϕζ dx − Z ∂Ω K∗ϕ∇ζ · ~ndσ − Z ∂Ω K∗ζ∇ϕ · ~n dσ + γh−1Z ∂Ω ϕζ dσ

where ϕ, ζ ∈ Sh, ~n is the unit outward normal vector on ∂Ω, K

is that in (2.2), and γ is some positive number. Now we find Uh∈ Sh such that

Lhγ(Uh, ζ) =

Z

|Yf|F ζdx for all ζ ∈ Sh. (2.6)

Here Uh is the numerical approximation of the solution of (1.3). By Lax-Milgram

theorem [9], (2.6) is solvable uniquely. Let us recall Theorem 3.1 [10].

Theorem 2.1. Suppose A4–A6 hold, U solves (1.3), Uh solves (2.6), and n = 2, 3. Let U ∈ Ws,∞(Ω) with max{m, 1} < s ≤ k, where m and k are the parameters in

A5 and k ≥ 3. Then there are constants γ1< ∞ and h1> 0 such that, for γ ≥ γ1

and 0 < h ≤ h1,

kU − UhkL∞(Ω)≤ chskU kWs,∞(Ω), (2.7)

where c is independent of h and U .

By A3 and Theorem 9.15 [9], we know U ∈ W2,∞(Ω). Lemma 2.2 and Theorem

2.1 imply that the maximum norm estimate of Uǫ− Uh(that is, difference between

the solution of (1.1) and the solution of (2.6)) satisfies kUǫ− UhkL∞(Ωǫ f)≤ kUǫ− U kL ∞(Ωǫ f)+ kU − U hk L∞(Ωǫ f) ≤ c(ǫ + h2)kF kW1,n+δ(Ω). (2.8)

where c is a constant independent of ǫ, h. In other words, if Lemma 2.2 holds, we have the following results:

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6 Error estimate

Theorem 2.2. Under A1–A6, there exist positive constants ǫ0, h1, γ1 such that

when ǫ ∈ (0, 1), λ ∈ [0, ǫ0), h ∈ (0, h1), and γ > γ1, the solution of (1.1) and the

numerical approximation in (2.6) satisfy the L∞

error estimate (2.8).

2.2. Lipschitz error estimate

In this subsection, functions considered are periodic and have period [0, 1]n for

n ∈ {2, 3}. If λ > 0 and F ∈ L2

per(Rn), we find Uǫ∈ Hper1 (Zfǫ) satisfying

(

−∇ · (Kǫ∇Uǫ) + λUǫ= F in Zfǫ,

Kǫ∇Uǫ· ~nǫ= 0 on ∂Zmǫ.

(2.9)

By Lax-Milgram theorem [9], (2.9) is solvable uniquely in H1

per(Zfǫ) and the solution

satisfies kUǫkH1

per(Zfǫ) ≤ ckF kL2per(Rn), where c is a constant independent of ǫ. By

compactness principle [2] and Lemma 2.1, there is a function U ∈ H1

per(Rn) such

that the solution Uǫ of (2.9) satisfies

( ΠǫUǫ→ U in Hper1 (Rn) weakly Kǫ∇UǫXZǫ f → K ∗ ∇U in L2 per(Rn) weakly as ǫ → 0 and U satisfies −∇ · (K∗∇U ) + λ|Yf|U = |Yf|F in Rn. (2.10)

Here |Yf| is the volume of Yf and K∗ is the positive definite matrix in (2.2).

Lemma 2.3. Under the following conditions A1′. δ ∈ (0, 3), α > 0, and Y

m is a C1,α domain,

A2 . K ∈ C1,α

per(Zf) is a positive function,

A3′

. F ∈ W2,n+δ per (Rn),

there is a constant ǫ0 < 1 such that the solutions of (2.9) and (2.10) satisfy, for

any ǫ ∈ (0, 1) and λ ∈ (0, ǫ0),

k∇Uǫ(x) − (I + ∇X(x/ǫ))∇U (x)kL∞(Zǫ

f)≤ cǫkF kWper2,n+δ(Rn), (2.11)

where c is a constant independent of ǫ.

Next we describe the finite element spaces to approximate the solution of (2.10). Let {Fh : 0 < h < 1} be a family of subdivisions of Rn into disjoint,

non-empty, connected, open sets τ ∈ Fh of diameter not greater than h (a subdivision

means Rn = ∪

τ ∈Fhτ ) and each subdivision is periodic with period [0, 1]n (that is,

τ + j ∈ Fhfor any τ ∈ Fh and j ∈ Zn). For r ≥ 2, Sh

r(Rn) is a family of finite

di-mensional subspace of W1,∞

per (Rn). If D ⊂ Rn, then Srh(D) (resp. Wper1,∞(D)) denotes

the restriction of functions in Sh

r(Rn) (resp. Wper1,∞(Rn)) to D. Let kh + di< di+1

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Error estimate 7

A7. If t ∈ {0, 1}, t ≤ ℓ ≤ r, 1 ≤ p ≤ ∞, then for each ϕ ∈ Wℓ,p(B

d2) there exists a ζ ∈ Sh r(Bd2) such that kϕ − ζkWt,p(B d1)≤ ch ℓ−tkϕk Wℓ,p(B d2). If n < p ≤ ∞, kϕ − ζkW1,∞(B d1)≤ ch r−1−n/pkϕk Wr,p(B d2).

Furthermore if ϕ vanishes outside of Bd0, ζ vanishes outside of Bd1. The

constant c is independent of h, ϕ, ζ, Bd1, and Bd2.

A8. If ζ ∈ Sh

r(Rn), then for t ∈ {0, 1} and ℓ ≥ 0 is an integer and 1 ≤ q ≤ p ≤ ∞,

kζkWt,p(B

d1)≤ ch

−(n/q−n/p)−t−ℓkζk W−ℓ,q(B

d2).

The constant c is independent of h, ζ, Bd1, and Bd2.

A9. Let ϕ ∈ C∞

0 (Bd1), then for each ζ ∈ S

h

r(Bd3) there exists an η ∈ S

h r(Bd3),

vanishing outside of Bd2, such that for some integer γ > 0

kϕζ − ηkH1(B

d3)≤ chkϕkWγ,∞(Bd1)kζkH1(Bd3).

Furthermore, if ϕ = 1 on Bd0, then η = ζ on Bd−1 and

kϕζ − ηkH1(B

d2)≤ chkϕkWγ,∞(Bd1)kζkH1(Bd2\Bd0).

Here c is independent of ϕ, ζ, η, h, Bd0, Bd1, Bd2.

A10. Let x0 ∈ Rn and d ≥ kh. The transformation y = x−xd 0 takes Bd(x0)

into a domain B1(x0) and Srh(Bd(x0)) into a function space ˆSrh/d(B1(x0)).

Then ˆSrh/d(B1(x0)) satisfies A7-A9 with h replaced by h/d. The constants

in A7-A9 remain unchanged, in particular independent of d.

Finite element spaces satisfying A7-A10 can be found in [15] and reference therein. We find Uh∈ Sh r(Rn) such that Z [0,1]n K∗∇Uh∇ζdx +Z [0,1]n λ|Yf|Uhζdx = Z [0,1]n |Yf|F ζdx, (2.12) where ζ ∈ Sh r(Rn). By A3 ′

and Theorem 9.11 [9], the solution of (2.10) satisfies U ∈ W4,n+δ

per (Rn). Theorem 3.1 [15] implies

Theorem 2.3. If A7-A10 hold, U ∈ W1,∞

per (Rn) solves (2.10), and Uh ∈ S4h(Rn)

solves (2.12), then there exists a constant c independent of U, Uh, h such that

kU − UhkW1,∞

per(Rn)≤ ch

3−n/(n+δ)kF k

Wper2,n+δ(Rn). (2.13)

Lemma 2.3, Theorem 2.3, and (2.5) imply that the Lipschitz norm estimate of Uǫ− Uh(that is, difference between the solution of (2.9) and the solution of (2.12))

satisfies

k∇Uǫ− (I + ∇Xǫ)∇UhkL∞(Zǫ

f)≤ c(ǫ + h

3−n/(n+δ))kF k

W2,n+δ([0,1]n), (2.14)

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8 Error estimate

Theorem 2.4. Assume A1′

, A2, A3′

, A7–A10. There exist positive constants ǫ0, h1

such that if ǫ ∈ (0, 1), λ ∈ (0, ǫ0), and h ∈ (0, h1), the solution of (2.9) and the

approximation in (2.12) satisfy the Lipschitz error estimate (2.14).

2.3. Higher order Lipschitz estimate Besides L∞

and Lipschitz error estimates, we also have higher order Lipschitz esti-mate. Functions in this subsection are periodic and have period [0, 1]nfor n ∈ {2, 3}.

If F ∈ L2 per(Rn) satisfies R [0,1]n∩Zǫ fF dx = 0, we find Uǫ∈ H 1

per(Zfǫ) such that

       −∇ · (Kǫ∇Uǫ) = F in Zfǫ, Kǫ∇Uǫ· ~nǫ= 0 on ∂Zmǫ, R [0,1]n∩Zǫ fUǫdx = 0. (2.15)

By Lax-Milgram theorem [9], (2.15) is solvable uniquely in H1

per(Zfǫ) and the

so-lution satisfies kUǫkH1

per(Zfǫ)≤ ckF kL2per(Rn), where c is a constant independent of

ǫ. By compactness principle [2] and Lemma 2.1, there is a function U ∈ H1 per(Rn)

such that the solution Uǫof (2.15) satisfies

( ΠǫUǫ→ U in Hper1 (Rn) weakly Kǫ∇UǫXZǫ f → K ∗ ∇U in L2 per(Rn) weakly as ǫ → 0 and U satisfies ( −∇ · (K∗ ∇U ) = |Yf|F in Rn, R [0,1]nU dx = 0. (2.16) Here |Yf| is the volume of Yf and K∗ is the positive definite matrix in (2.2).

Theorem 2.5. Under A1′, A2, and

A3′′

. F ∈ Wk,n+δ

per (Rn) for k ≥ 2,

the solutions of (2.15) and (2.16) satisfy, for any ǫ ∈ (0, 1), k∇ϕǫkL∞(Zǫ

f)≤ cǫ

k−1kF k

Wperk,n+δ(Rn).

where c is a constant independent of ǫ and ϕǫ(x) ≡ Uǫ(x) − U (x) − k X ℓ=1 ǫℓ n X i1,...,iℓ=1 X(i1,...,iℓ)(x ǫ)∂i1,...,iℓU (x). References

1. E. Acerbi, V. Chiado Piat, G. Dal Maso, and D. Percivale, An extension theorem from connected sets, and homogenization in general periodic domains, Nonlinear Analysis 18 (1992) 481–496.

2. Gregoire Allaire, Homogenization and two-scale convergence, SIAM I. Math. Anal. 23 (1992) 1482–1518.

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October 28, 2010

Error estimate 9

3. N. Bakhvalov and G. Panasenko, Homogenisation : averaging processes in pe-riodic media : mathematical problems in the mechanics of composite ma-terials (Kluwer Academic Publishers, 1989).

4. Susanne C. Brenner, L. Ridgway Scott, The mathematical theory of finite ele-ment methods (Springer, 2008).

5. Alain Bensoussan, Jacques-Louis Lions, George Papanicolaou, Asymptotic analysis for periodic structures (Elsevier North-Holland, 1978).

6. Li-Qun Cao, Asymptotic expansions and numerical algorithms of eigenvalues and eigenfunctions of the Dirichlet problem for second order elliptic equations in perfo-rated domains, Numerische Mathematik 103 no. 1 (2006) 11–45.

7. Philippe G. Ciarlet, The finite element method for elliptic problems (Amster-dam : North-Holland, 1978).

8. M. Giaquinta, Multiple integrals in the calculus of variations, (Study 105, Annals of Math. Studies, Princeton Univ. Press., 1983).

9. D. Gilbarg, N. S. Trudinger Elliptic Partial Differential Equations of Second Order. Springer-Verlag, Berlin, second edition, 1983.

10. C. I. Goldstein, L. R. Scott, Optimal maximum norm error estimates for some finite element methods for treating the Dirichlet problem , Calcolo 20 1 (1983) 1–52. 11. V.V. Jikov, S.M. Kozlov, O.A. Oleinik, Homogenization of Differential

Opera-tors and Integral Functions, (Springer-Verlag, 1994).

12. O. A. Ladyzhenskaya, Nina N. Ural’tseva Elliptic and Quasilinear Elliptic Equations. Academic Press, 1968.

13. J.L. Lions, Asymptotic expansions in perforated media with a periodic structure, The ROcky Mountain J. Math. 10(1) (1980) 125–144.

14. O.A. Oleinik, A.S. Shamaev, G.A. Tosifan, Mathematical Problems in Elasticity and Homogenization (North-Holland, Amsterdam, 1992).

15. Alfred Schatz, Pointwise error estimates and asymptotic error expansion inequalities for the finite element method on irregular grids: Part I. Global estimates, Mathematics of Computation Vol. 67 No. 223 (1998) 877–899.

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參加會議經過

2010 年 SIAM 年會是在美國賓州的匹茲堡 (Pittsburg)市舉行。時間由九十九

年七月十二日至十六日共五天。會議的主題包含了大氣物理、洋流、地球科

學、電磁學、生物數學、材料學、影像處理、計算方法等。演講內容包含有問

題的模式的推導、計算方法的設計、及數學性質的探討。我的報告時間是安排

在會議的第二天上午。講題是``Numerical Methods for Elliptic and Parabolic

Equations in Perforated Domains”

。主要是介紹如何有效率的得到橢圓方程式與

拋物線方程式在 Perforated Domains 的解。

與會心得

和往年一樣我都會參加一些與我的研究主題相關的 session。參加完這次會議

我的最大的心得就是對 point source 的了解。它主要是描述在很小的範圍內有很

大的外加進來的 source 情形。point source 在很多的應用問題上都會出現,如材

料力學、地球科學、流體力學、地質學等的研究都可能會遇到 point source 這問

題。在橢圓形方程式或拋物線方程式的 Green function 即為對應到 point source 的

解,關於 Green function 在數學上已經有很多的研究,大家對它也有一定程度的

了解。在數值計算上,無論是有限差分法、有限元素法、或是 finite volume

method 也都有簡單的方法來處理 point source。一切看起來似乎都很美好,point

source 在數學理論上、在數值計算上不應該給我們造成任何的困擾。不過再仔

細想一想有 point source 與沒有 point source 最大的差異是甚麼?我覺得最大的差

異是在 point source 附近壓力與流速趨近於無限大,而且在一般情形下它幾乎無

法計算。若是我們只在乎整體的變化,則 point source 的計算倒是容易,畢竟它

只佔整個區域的極少部份,即使 point source 附近的計算有很大的誤差,它對整

體的影響還是很小,所以一般的有限差分法、有限元素法、或是 finite volume

method 都能處理 point source 的問題。但若是我們在乎每一個小範圍的變化,則

point source 附近的計算就很重要了。譬如需要保有每一個小範圍都有質量守恆

性質的數值計算方法,就在乎每一個小範圍的變化。真正從是計算它的值,即

可發現它的困難度。我的最大的心得就是對如何計算 point source 附近的的壓力

與流速找到了一個好的辦法。

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(24)

98 年度專題研究計畫研究成果彙整表

計畫主持人:

葉立明

計畫編號:

98-2115-M-009-011-計畫名稱:

破裂介質中的熱傳導方程式

量化

成果項目

實際已達成

數(被接受

或已發表)

預期總達成

數(含實際已

達成數)

本計畫實

際貢獻百

分比

單位

備 註

質 化 說

明:如 數 個 計 畫

共 同 成 果、成 果

列 為 該 期 刊 之

封 面 故 事 ...

期刊論文

0

0

100%

研究報告/技術報告

2

2

100%

研討會論文

0

0

100%

論文著作

專書

0

0

100%

申請中件數

0

0

100%

專利

已獲得件數

0

0

100%

件數

0

0

100%

技術移轉

權利金

0

0

100%

千元

碩士生

2

2

100%

博士生

0

0

100%

博士後研究員

0

0

100%

國內

參與計畫人力

(本國籍)

專任助理

0

0

100%

人次

期刊論文

0

0

100%

研究報告/技術報告 0

0

100%

研討會論文

0

0

100%

論文著作

專書

0

0

100%

章/本

申請中件數

0

0

100%

專利

已獲得件數

0

0

100%

件數

0

0

100%

技術移轉

權利金

0

0

100%

千元

碩士生

0

0

100%

博士生

0

0

100%

博士後研究員

0

0

100%

國外

參與計畫人力

(外國籍)

專任助理

0

0

100%

人次

(25)

其他成果

(

無法以量化表達之成

果如辦理學術活動、獲

得獎項、重要國際合

作、研究成果國際影響

力及其他協助產業技

術發展之具體效益事

項等,請以文字敘述填

列。)

成果項目

量化

名稱或內容性質簡述

測驗工具(含質性與量性)

0

課程/模組

0

電腦及網路系統或工具

0

教材

0

舉辦之活動/競賽

0

研討會/工作坊

0

電子報、網站

0

目 計畫成果推廣之參與(閱聽)人數

0

(26)
(27)

國科會補助專題研究計畫成果報告自評表

請就研究內容與原計畫相符程度、達成預期目標情況、研究成果之學術或應用價

值(簡要敘述成果所代表之意義、價值、影響或進一步發展之可能性)

、是否適

合在學術期刊發表或申請專利、主要發現或其他有關價值等,作一綜合評估。

1. 請就研究內容與原計畫相符程度、達成預期目標情況作一綜合評估

■達成目標

□未達成目標(請說明,以 100 字為限)

□實驗失敗

□因故實驗中斷

□其他原因

說明:

2. 研究成果在學術期刊發表或申請專利等情形:

論文:□已發表 ■未發表之文稿 □撰寫中 □無

專利:□已獲得 □申請中 ■無

技轉:□已技轉 □洽談中 ■無

其他:(以 100 字為限)

3. 請依學術成就、技術創新、社會影響等方面,評估研究成果之學術或應用價

值(簡要敘述成果所代表之意義、價值、影響或進一步發展之可能性)(以

500 字為限)

1. H\''''older estimate for non-uniform parabolic equations in highly

heterogeneous media

此 篇 論 文 研 究 的 方 程 式 是 non-uniform parabolic equations with discontinuous

coefficients.從文獻中我們知道 uniform parabolic equations with discontinuous

coefficients 及 non-uniform parabolic equations with smooth coefficients 有人研

究過.以上兩種情況下解都有可能是平滑的.但是我們考慮的方程式的解是否平滑要看是

在甚麼區域.這與之前的認知很不同.在學術上,這是值得繼續深究的.在實際問題上,一如

成果報告中所述是很有應用價值的研究. 此篇論文研究的成果告訴我們在各個不同區域

的平滑性.

2.Pointwise error estimate for elliptic equations in perforated domains

它的重要性在很多的文獻中都可看出.這裡不再贅述. 此篇論文則告訴我們每一點的誤差

估計.

參考文獻

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