Question re: making interior nodes

Hello, so I am trying to make a mesh of nodes that will scale according to mesh size. Here's the code I have so far:

%%Set Parameters

k = 10; %W/mK
h = 30; %W/m^2K
q_dot = 25000; %W/m^2
T_inf = 298.15; %Kelvin
T1 = 283.15; %Kelvin
T2 = 298.15; %Kelvin

prompt = 'n = ';
n = input(prompt) %Nodes numbering in x-dir.

nodes = 1:n*n; %Node numbers
%%Matrix Population

NT = zeros(length(nodes),1);
T = (n+1):n:nodes(end); 
B = n:n:nodes(end); 
L = (3*n+3):n:((n+3)+6*n);
M = (3*n+4):n:((n+4)+6*n);

for i=1:length(nodes)
    if i==1
        NT(i)=1; %Top-left corner
    elseif i>1 && i<n
        NT(i)=8; %Left edge
    elseif ismember(i,T)
        NT(i)=2; %Top edge
        NT(T(end))=3; %Top-right corner
    elseif i==nodes(end)
        NT(i)=5; %Bottom-right corner
    elseif i==n
        NT(i)=7; %Bottom-left corner
    elseif i>T
        NT(i)=4; %Right edge
    elseif ismember(i,B)
        NT(i)=6; %Bottom Edge
    elseif ismember(i,L)
        NT(L)=10; %Area of heat generation, row 1
    elseif ismember(i,M)
        NT(M)=10; %Area of heat generation, row 2
    else
        NT(i)=9; %Adiabatic area
    end
end

node_reshape = reshape(NT,n,n);

The problem child I'm dealing with are these two lines:

    elseif ismember(i,L)
            NT(L)=10; %Area of heat generation, row 1
        elseif ismember(i,M)
            NT(M)=10; %Area of heat generation, row 2

Those lines are supposed to create for me a rectangular 2x5 node grid which is where the heat generation will take place, at a specific location. And it does--for a mesh size of 10x10 (when you input n=10, according to the prompt). Unfortunately, when I try to scale up or down (like, for example, setting n=20 for a 20x20 grid), that 2x5 grid won't scale upwards in size, which is an issue because the project gets a zero percent score if the code can't handle a variable size. Thus, I need an alternate solution, and I don't know enough about MATLAB to figure out how to find it. I was hoping there might be someone here who might be able to make some suggestions about how I should go about this?

Thanks in advance.

Answer 1

[KSSV]

For meshing a rectangular/ square region with node numbers, you can have a look on this link: https://in.mathworks.com/matlabcentral/fileexchange/33731-meshing-a-plate-using-four-noded-elements?focused=5204259&tab=function

[Zachary McCormick]

Interesting! Wouldn't making use of that model mean throwing out the rest of the code I've already written, though? I'm not really jazzed about the idea of undoing hours' worth of work. I'm mostly just looking for an if statement that can replace the few lines I pointed out in the OP.