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-   -   sormon.f usage for fixing a constant velocity for defined cellset (https://www.cfd-online.com/Forums/star-cd/69698-sormon-f-usage-fixing-constant-velocity-defined-cellset.html)

 Tilak November 1, 2009 08:06

sormon.f usage for fixing a constant velocity for defined cellset

Dear All,

Our question is related to startcd internal boundry condition setting. We wanted to use the internal boundary condition at the several outlets of the blower which are again connected back to the inlet through flow circuit and some portion of fluid is discarded through outlets located inbetween the circuit. We know the CFM of every blower ie velocity at every blower outlet. For this reason, we thought of using the sormom.f. So thought, if we select the cell sets at the outlet of the blowers where we know the velocities and define it through sormom.f for the corresponding ictid. Pls correct us if we are wrong here.

We performed a test in a small test channel where we set the inlet velocity as w=-0.5m/s as per the -ve 'z' direction at the inlet. We are using sormom.f for the cell set when (ictid .eq. 11) - to set the"w" velocity to 1.0 m/s (not clear of -ve or +ve as per the dirn - the w velocity direction is agin -ve 'z' dirn). The total ength of the channel is 1 m and cross-section is 0.1 X 0.1 m and the cell set no 11 is somewhere in the middle having enough cell layers in the flow direction.

But unfortunately we are unable to get the result of 1 m/s in that cell set. Rather it appears, eventhough the sormom.f is getting visited every time at every run but the result is same for any change in the s1w and s2w - even it is "0.0" or any number there the result is same as with or without sormom.

We used the following sormom.f

IF(ICTID .EQ. 11) THEN
s1u = 0.0
s1v = 0.0
s1w = - 1.0 * great
s2u = 0.0
s2v = 0.0
s2w = great
ENDIF

RETURN
END

Pls let us know the proper usage or other method to define the known velocity at certain cell sets without disturbing the other flow parameters/values such as T,P,Rho,k,e,u and v as well.

Early reply would be greatly appreciated.