why downstream height is defined?
hi, can anybody tell why we are using downstream height downH in the tutorial problem no 7 of flow over free surface bump? i am confused, what will happen if we remove that expression.
is there any effect on the outflow side? |
Re: why downstream height is defined?
For an outlet boundary condition , in CFX , you have to specify volume fractions for each fluid . You can avoid this specification by changing it to an opening with a sepcified pressure. or in outlet change volume fractions to zero gradient.
|
Re: why downstream height is defined?
thank MAB,
this is correct, ifwe take some pressure, the result would be same , but in my case, there is a twist in the problem: i am continuing this problem by looking hydraulic jump after and over the bump. i simply take static pressure value at outlet, the results differ from the previous cases when i used downstream height. i just want to know, what is the fluid mechanics fundamental involve with this outflow boundary condition? thanks. |
Re: why downstream height is defined?
thank MAB,
this is correct, if we take some pressure, the result would be same , but in my case, there is a twist in the problem: i am continuing this problem by looking hydraulic jump after and over the bump. i simply take static pressure value at outlet, the results differ from the previous cases when i used downstream height. i just want to know, what is the fluid mechanics fundamental involve with this outflow boundary condition? thanks. |
Re: why downstream height is defined?
with this post, i want to ask one more thing is that.
if downstream height is defined, what should be its height? how it is considered?? |
Re: why downstream height is defined?
I think they used a lower height at downstream as compared to the one at inflow boudary. The reason is that water level would decrease gradually as the water goes out of the tank . so the downH is the rough estimate of this lower level.
You can even keep the level same as at inflow boundary. |
All times are GMT -4. The time now is 11:18. |