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-   -   Aerospike flow 3rd order (https://www.cfd-online.com/Forums/fluent/86908-aerospike-flow-3rd-order.html)

 dim_slo April 5, 2011 22:22

Aerospike flow 3rd order

I have a few questions concerning a 1st and 3rd order 'solution'. Below is a pic of my grid (~2.2 million):

http://www.cfd-online.com/Forums/mem...-aero-mesh.jpg

I first wanted to solve for a 1st order solution with a pressure inlet and pressure outlet and laminar turb as a simple starting point. My question about the 1st order solution is about the convergence. Is is typical for the 'other' velocities to not converge to a low value like shown in the pic below? Even the other values converge to only ~10-2:

http://www.cfd-online.com/Forums/mem...inar-resid.jpg

Here is a pic of the mach contour:

http://www.cfd-online.com/Forums/mem...minar-mach.jpg

The residuals didn't converge to a low number but the flow looks right and the mass flux balances correctly.

 dim_slo April 5, 2011 22:25

When I use the first order case to start the 3rd order solution (3rd order MUSCL), the flow becomes unstable at the outlet boundary, is this typical of a higher order solution (problems near the boundary)?

http://www.cfd-online.com/Forums/mem...minar-mach.jpg

http://www.cfd-online.com/Forums/mem...inar-resid.jpg

Can anyone help me out with what I'm doing wrong?

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