Solution process for supersonic ramped-inlet
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Supersonic ramped inlet problems are difficult to run. The incoming flow is supersonic (Mach 2-3) and the fan face has a high pressure and the flow is subsonic. It is difficult to specify good initial condition. A two-step solution process has been developed: 1st Step (sample-2d-plugged.cas.gz, sample-2d-plugged.dat.gz) -------- - Use the segregated solver - Load the case file - Set the "ramp-out" zone to wall - Set the incoming freestream boundary to be pressure-farfield - Set the outgoing freestream boundary to be pressure-outlet - Set the proper solution limits - Initialize using the full freestream value - Set the boundary for the fan face to wall and iterate until first-order convergence is achieved (about 2000-3000 iterations) At convergence, the average pressure at "ramp-out" is ~8.5atm This means that the pressure at this boundary will be the maximum pressure possible (p-max-outlet) Thus, if this boundary is changed to pressure-outlet type and the pressure value is set to p-max-outlet then there will be little or no flow through this boundary For flow to go out through this boundary, the pressure must be lower than the p-max-outlet 2nd Step (sample-2d-final.cas.gz, sample-2d-final.dat.gz) -------- - Change the boundary type at fan-face to pressure-outlet Use a pressure value that is slightly lower than p-max-outlet Iterate for sufficient convergence - Gradually lower the pressure value until the desired level is achieved (i.e. 8.0atm) Files for the sample problem can be found at: <a target=_blank href="http://www.fluentusers.com/support/solutions/1019/supersonic-ramp-inlet.zip">http://www.fluentusers.com/support/solutions/1019/supersonic-ramp-inlet.zip</a>http://www.fluentusers.com/support/solutions/1019/supersonic-ramp-inlet.zip |
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