Confusion Regarding Inlet Boundary Condition for Detonation Simulation
 

Hello everyone,

I am currently attempting to perform a numerical simulation of detonation within a 3D cylinder, as shown in Figure-1. However, I am facing some confusion regarding the definition of density and reactant density for the inlet boundary condition, as depicted in Figure-2.

Based on the literature review, I understand that I can use the equation of state, which is enclosed in a box within Figure-2. However, when I apply this method, I am observing a significantly high-density gradient at the wall (Figure-3). Since the wall has no inflow, shouldn't the density gradient be much lower? In other words, I expect the density gradient to be very minimal.

Would it be reasonable to use the same density gradient as the cells located next to the wall as an alternative? Does this sound like a logical approach?

Thanks,

I think the gradient that you see is because the solver is diverging. Try much smaller dt and see.

Thank you for responding.
The contour figures display the initial conditions at time zero, and I have not yet commenced the simulation. The computed density value is solely based on the boundary conditions depicted in Figure-2.

Then there are only 2 possibilities here.

1 you did not set it up properly (temperature and pressure)

2 software has a bug.

For bc i highly doubt that software has bug so carefully check how you are setting it up.

Walls shall have same density as near by cell.