Computational domain for a blade cascade

aledexe · June 2, 2012, 04:13

Hello everybody,
I am going to analyze the flow within a compressor blade passage and I know about the possibility to study a single blade, and then applying the periodic boundaries to the upper and lower side of the domain. My questions are:
- which are the shapes of the surfaces on which I have to apply the periodicity?
- how are these shapes affecting the results, i.e. how is the periodicity acting at the interfaces?

I attach a picture of a domain corresponding to my blade geometry that I found on some articles. Thanks in advance for any help!

ghorrocks · June 2, 2012, 07:28

Ideally the shape of the periodic boundary does not affect the results. There are a few pitfalls to avoid - like it should not cut through a blade (and if it has to it should do it perpendicular to the surface and not in a critical flow region), it should avoid the wake of the blade, and if possible it should avoid any shocks/rarefaction waves (but this can be very difficult to do, just minimise it as best you can).

But if you have a good mesh quality and a well converged solution you can get away with some of these sins.

aledexe · June 3, 2012, 07:43

Thanks for the help

June 2, 2012, 04:13	Computational domain for a blade cascade	#1
aledexe New Member Alessio Join Date: May 2012 Posts: 9 Rep Power: 14	Hello everybody, I am going to analyze the flow within a compressor blade passage and I know about the possibility to study a single blade, and then applying the periodic boundaries to the upper and lower side of the domain. My questions are: - which are the shapes of the surfaces on which I have to apply the periodicity? - how are these shapes affecting the results, i.e. how is the periodicity acting at the interfaces? I attach a picture of a domain corresponding to my blade geometry that I found on some articles. Thanks in advance for any help!

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June 2, 2012, 07:28		#2
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,871 Rep Power: 144	Ideally the shape of the periodic boundary does not affect the results. There are a few pitfalls to avoid - like it should not cut through a blade (and if it has to it should do it perpendicular to the surface and not in a critical flow region), it should avoid the wake of the blade, and if possible it should avoid any shocks/rarefaction waves (but this can be very difficult to do, just minimise it as best you can). But if you have a good mesh quality and a well converged solution you can get away with some of these sins.

June 3, 2012, 07:43		#3
aledexe New Member Alessio Join Date: May 2012 Posts: 9 Rep Power: 14	Thanks for the help