Flow over a backward facing step

The Domain size was assumed as follows:

and scaled down to 1/10 times as a limitation of no. of cells.

The Backward Step flow was set up for the following conditions:

Cell Size Cycles

1. 2e-4 15,000

2. 1.5e-4 15,000

3. 1e-4 20,000

In all the conditions, the flow velocity at steady state was found to be 160 m/s. However, the results converged lately as the mesh size increased, which forced the no. of cycles to be increased to 20,000 and solve using Density-Based steady solver the 3rd condition.

The 3rd Condition reached Steady state after 19,000 cycles. In concern of the Computational resource and time, the cycles were not increased further.

Also, due to the turbulence nature, with high no of cells, the solver spent more time to solve and attain convergence to thr result which can be observed from minute fluctuations in the curve after 14,000 cycles but, with no constant result upto 19,000 cycles.

The above conclusion can be easily observed from the below results: