I have written a simple C++ code for flow over cylinder (2D).
Parameters for coding are as follows;
Rep = 4
nx = 500
ny = 80
Dp = 10
Lx = 125 (x-direction particle position)
Ly = 40
@ inlet = uniform velocity corresponding to Rep = 4
@ outlet = extrapolation BC (zero gradient)
@ cylinder surface = Mei BC ([Mei_1999]_An_accurate_boundary_treatment_in_the_LBM)
all calculations were done using tau = 0.6
Code is running fine, till certain time step force goes on increasing and reaches to stable value but after that
the value of force starts dropping and continue till infinity.
Can anybody please have a look on code and suggest me some correction to remove above mentioned problem.