# Darcy's law

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hasan damaj 2019 年 12 月 7 日
Commented: hasan damaj 2019 年 12 月 12 日
clc
clear
% Laplace equation
% Define the length of the grid
L = 5 ;
% Define the Width of the grid
B = 5 ;
nx = 4 ;
ny = 4 ;
dx = 100;
dy = 100;
h=zeros(nx,ny);
amax = 0;
% boundry conditions
h(1,:) = [ 8.04 , 7.68 , 7.19 , 6.82 ];
h(nx,:) = [ 8.53 , 8.41 , 8.33 , 8.29 ];
h(:,1) = [ 8.04 , 8.18 , 8.36 , 8.53 ];
h(:,ny) = [ 6.82 , 7.56 , 7.99 , 8.29 ];
while amax <= 0.01
for j = 2 : nx-1
for i = 2 : ny-1
oldval = h(i,j);
h(i,j) = ( h(i-1,j) + h(i+1,j) + h(i,j-1) + h(i,j+1)/4) ;
e = abs(h(i,j)) - oldval;
if e > amax
amax = e;
end
end
end
end
h
I NEED TO GET TO THE FOLLOWING RESULT
8.04 8.18 8.36 8.53
7.68 7.93 8.19 8.41
7.19 7.68 8.05 8.33
6.82 7.56 7.99 8.29
Can you suggest for me the correction and thank you :)

#### 7 件のコメント

darova 2019 年 12 月 11 日
Did you try to divide all elements? NOt only last one
h(i,j) = ( h(i-1,j) + h(i+1,j) + h(i,j-1) + h(i,j+1))/4 ;
hasan damaj 2019 年 12 月 11 日
the equation is correct sir..
hasan damaj 2019 年 12 月 11 日
the while condition is not working with me

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### 件の回答 (1)

Image Analyst 2019 年 12 月 7 日
You're setting up your boundary conditions incorrectly. You're overwriting the corners with different numbers. I think maybe you want this:
% Initialize boundary conditions:
h(1,:) = [ 8.04 , 7.68 , 7.19 , 8.53];
h(end,:) = [6.82 , 7.56 , 7.99 , 8.29 ];
h(2:3,1) = [7.68;7.19];
h(2:3,end) = [8.41; 8.33];
h
% Here h should be
% 8.04 8.18 8.36 8.53
% 7.68 0 0 8.41
% 7.19 0 0 8.33
% 6.82 7.56 7.99 8.29

#### 7 件のコメント

hasan damaj 2019 年 12 月 11 日
hasan damaj 2019 年 12 月 11 日
but the values of inner index are zeros after running the code..
hasan damaj 2019 年 12 月 12 日
how do i edit it to reach my results and thank you

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R2019a

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