[mojtabaivi]

Hi everybody;

I'm working on the hydraulic jump phenomena. I've face a problem, It's needed to start hydraulic jump at specified location (right at the inlet boundary, 20 mm after inlet boundary, etc). what should I do?
I use "outflow" condition for outlet, and place a block at the end of channel to form hydraulic jump. so, the sequent depth and location of hydraulic jump is depend on the block height and location. but I wanna the hydraulic jump to start at an specified location I said above. Is there a better way for It? for example special boundary condition or ...?

Thank you,
Mojtaba

[Taimoor Ahmad]

Can you please post picture of the model for better understanding?

[mojtabaivi]

of course;



I want to hydraulic jump starts right at the red star location

[Taimoor Ahmad]

If the hydraulic jump is being formed further downstream, have you tried bringing the block upstream to force the hydraulic jump formation at your desired location?

[mojtabaivi]

Originally Posted by Taimoor Ahmad

If the hydraulic jump is being formed further downstream, have you tried bringing the block upstream to force the hydraulic jump formation at your desired location?

yes I tried it. but it's really difficult to find the proper block location by trial and error method. I want to know that is there any method to force the jump formation at a desired location or any way to calculate the jump location?

[Taimoor Ahmad]

There are formulae to calculate the length of jump,L.

L = 220 x y1 x tanh((Fr1-1)/22)

Reference: Hager, W.H. 1992. Energy Dissipators and Hydraulic Jump. Kluwer Academic, Dordrecht, The Netherlands. ISBN 0-7923-1508-1