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Kumudu October 24, 2013 14:08

Time varying ambient temperature as B.C in OpenFoam

I am working on a problem related to ground source heat pump simulations . I want to simulate ground temperature using LaplacianFoam. My boundary conditions are as follows,

Top: T(0,0,0,t)=20.5+21.5*cos(2*pi/12*(t-7));
All other boundaries : No heat flux

Computational domain is a simple cube with 5m*5m*40m.
I want to set the time step and time loop follows the following logic in Laplacian solver,

P { margin-bottom: 0.08in; direction: ltr; color: rgb(0, 0, 0); widows: 2; orphans: 2; }

Nt = 5000; % Choose the number of time steps
dt = (365*24*60*60)/Nt; %Length of each time step in seconds
% Initial guess is that T is 15 everywhere.
time = [0:12/Nt:12];
T(0,0,0,t) = 20.5+21.5*cos(2*pi/12*(time-7));

I have solved this problem in Matlab using 1D diffusion equation, but, I want to try it in OpenFoam for 3D case and compare the solutions. Since, finally using above said B.C I will obtain 1D temperature distribution as a function of depth.

Please, can anyone help me to change the time steps as above and help me to define ambient temperature as a boundary condition at the top as a changing value with time.


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