how to define bc for a oscillating flow output?
 

Hi,

The output is an oscillating one which has large volumn output and then little volumn reversed flow. I defined the oscillating boundary as 'outflow' but it seems an error as 'reversed flow in 4 faces on outflow 6'.
Could anyone told me which type I should define this bc? Thanks.

Itsqi7

You should use pressure inlet for both outlet and inlet. For more configuration you should use a DEFINE_PROFILE udf.

Thanks for ur reply. I'll try that.

Hi, Saeed. I tried to use pressure inlet but the warning still happened. I think maybe FLUENT thought there is no fluid beyond the inlet and outlet, so when there is backflow it reports. Can I define, as I suppose, there is infinite fluid at the other sides of inlet and outlet?
My pump structure is as following.
Attachment 18535
Thanks for ur kind help.

Regards,
itsqi7

It's better to add a channel to inlet and outlet, could get a better results.

Thanks. By the way, how could I define that channel?