Find answers, ask questions, and connect with our <br>community around the world.

Home Forums CFD foundation course: Forum FDM : UNSTEADY PROBLEMS(LECTURE 11) Reply To: FDM : UNSTEADY PROBLEMS(LECTURE 11)

  • PRASHANT

    Member
    July 1, 2022 at 2:37 pm

    I have one more doubt
    clc
    clear all
    % Geometrical parameters

    xmin=0;
    xmax = 0.2; % Length of Rod
    N=50; % No of Nodes
    dx=(xmax-xmin)/(N-1); % grid size
    x=xmin:dx:xmax;
    dt=1e-4 % time step size
    tmax=0.2; % Max time to simulate
    t=0:dt:tmax;
    alpha= 0.05; % diffusion coefficient

    % Initial and Boundary conditions

    Tcurrent = ones(1,N)*30; % initial condition
    Tb = 300; % Boundary condition,T base
    Ttip = 50; % Boundary condition, T tip

    % solution

    d=alpha*dt/dx^2
    for j=2:length(t) % loop for time step
    T=Tcurrent
    end
    for i=1:N % Space Stepping
    if i==1
    T(i)=Tb;
    else if i==N
    T(i)=Ttip;
    else
    T(i)=T(i)+d*(T(i+1)-2*T(i)+T(i-1));
    end
    end
    Tcurrent=T;
    time=j*dt;
    plot(x,Tcurrent)
    xlabel(‘Length of rod [m]’,’FontSize’,14)
    ylabel(‘Temperature [^{0}C]’,’FontSize’,14)
    set(gca,’Fontsize’,16)
    str1= sprintf(‘value of d = %d’,d);
    str2= sprintf(‘Time value = %dS’,time);
    text(0.12,150,str1,’FontSize’,14);
    text(0.12,130,str2,’Fontsize’,14);

    shg
    pause(0.01)
    end

    Solution is not converging………………graph obtained is still a curve and not a straight line…………..

error: Content is protected !!