2D diffusion equation for a laser heat source

9 次查看(过去 30 天)
I am writing a code for laser source. However, when I am incorporating the source term, I am getting an error saying mismatch of array dimensions. I also want a plot between temperature and time. How to do that? Is there any issue with the CFL condition?
clc;
clear all;
% Parameters
rho=2600;
cp=473;
% domain and step
Lx=10;
Ly=10;
Nx=51;
Nt=3000;
Ny=51;
dx=Lx/(Nx-1);
dy=Ly/(Ny-1);
%CFL condition
c=1;
C=0.05;
dt=(C*dx/c);
%field variables
Tn=zeros(Ny,Nx);
x=linspace(0,Lx,Nx);
y=linspace(0,Ly,Ny);
[X,Y]=meshgrid(x,y);
q_dot=2.36*10^14*exp(-(800)*((x).^2+(y).^2));
K=ones(Ny,Nx);
K(1:Lx,1:Ly)=0.078;
%Initial condition
Tn(:,:)=0;
t=0;
%Loop
for n=1:Nt
Tc=Tn;
t=t+dt;
for i=2:Nx-1
for j=2:Ny-1
Tn(j,i)=Tc(j,i)+ ...
dt* (K(j,i)/rho/cp)*...
((Tc(j,i+1)+Tc(j+1,i)-4*Tc(j,i)+Tc(j-1,i)+Tc(j,i-1))/dx/dx);
end
end
%Source term
Sx=round(5.1*Nx/Lx);
Sy=round(9.9*Ny/Ly);
if (t<3)
Tn(Sy,Sx)=Tn(Sy,Sx)+dt*q_dot/rho/cp;
end
%Boundary condition
Tn(1,:)=0;
Tn(end,:)=0;
Tn(:,1)=0;
Tn(:,end)=Tn(:,end-1);
%Visualize
mesh(X,Y,Tn);
axis([0 Lx 0 Ly 0 50]);
title(sprintf('Time=%f seconds',t))
pause(0.1);
end
Unable to perform assignment because the size of the left side is 1-by-1 and the size of the right side is 1-by-51.

回答(1 个)

Torsten
Torsten 2023-8-13
编辑:Torsten 2023-8-13
qdot is 1x51, T(Sy,Sx) is a scalar. Thus
Tn(Sy,Sx)=Tn(Sy,Sx)+dt*q_dot/rho/cp;
tries to assign an array to a scalar which throws an error.
And why do you mix lengths and number of elements and switch between x and y in the definition of K ?
K=ones(Ny,Nx);
K(1:Lx,1:Ly)=0.078;
  2 个评论
AD
AD 2023-8-13
Ik why I am getting the error? But how to fix it?
Torsten
Torsten 2023-8-13
编辑:Torsten 2023-8-13
In what region of your domain do you want to set the source term ? And how should the source term look like in this subdomain ?
"qdot" in your code is a vector of size 1x51, and you are lucky that Nx = Ny, otherwise MATLAB would have thrown an error when you compute "qdot" as
q_dot=2.36*10^14*exp(-(800)*((x).^2+(y).^2));
It is not obvious how "qdot" of size 1x51 is related to the domain which has a 51x51 grid.
Maybe you want
q_dot=2.36*10^14*exp(-(800)*((X).^2+(Y).^2));
I don't know.

请先登录,再进行评论。

类别

Help CenterFile Exchange 中查找有关 Statics and Dynamics 的更多信息

产品


版本

R2022b

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by