Discussion Groups

Simulation Mechanical and Multiphysics

Reply
Active Contributor
jorge.lopera
Posts: 35
Registered: ‎09-21-2006

OPEN CHANNEL ANALYSIS - Results Interpretation

200 Views, 4 Replies
12-04-2012 09:16 PM

Hi,

 

I have to calculate the time to drain a tank, I have found some formulas, but I wish to know If Simulation Multiphysics it has any way to interpretate the results, this is the workflow what I followed:

 

1. Import a CAD model  from SImulation MP, for example a cylinder with a little extrude to represent the outlet.

2. Define the mesh, for boundary layer.

3. Define the Top surface as a inlet/outlet, and the bottom surface too, this two surfaces must be for exclusion for boundary layer.

4. Define like 5 seconds (Pparameters) with different steps between each second.

5. Check that the gravity is working.

6. Then Run de analysis.

 

 

The question is, If I use the equation for fluid drain in a tank or recipent, that equation gives me an idea for the time that the fluid leaves the recipient. For example:

t=(A√(2h_1 ))/(〖A_o C〗_q √g)

But, when I define the Open Channel Model Parameters, define a time, like 10 seconds.,with several steps for each second.

 

For example, when I run, I have just see the results. That results appears like the flow it has continusly flow, not likes the aire displace the water. Y have just tried to read the User Guide (http://wikihelp.autodesk.com/Simulation_Mechanical/enu/2013/Help/0031-Autodesk31/0193-Analysis193/02...).

 

Then I need to estimate an approach about the time that I need to evacuate a fluid from a tank.

 

Please any help y I will aprecciate.

 

Regards,

Technical Specialist
Nexsys de Colombia
Please use plain text.
Valued Mentor
AstroJohnPE
Posts: 494
Registered: ‎08-30-2012

Re: OPEN CHANNEL ANALYSIS - Results Interpretation

12-04-2012 09:40 PM in reply to: jorge.lopera

Hello Jorge,

 

This may be a silly question, but what is the analysis type set to? (It should be set to Open Channel.)

 

I think you only need to define an inlet/outlet surface on the outlet of your model. There is no water entering the top of the model, so that surface is not an inlet/outlet.

 

Also, you did not mention that you defined the initial volume (model either completely filled or partially filled), but I assume you did that.

 

John Holtz, PE
Mechanical Engineer
Pittsburgh, PA

16 years experience with Simulation Mechanical
Please use plain text.
Active Contributor
jorge.lopera
Posts: 35
Registered: ‎09-21-2006

Re: OPEN CHANNEL ANALYSIS - Results Interpretation

12-05-2012 05:01 AM in reply to: jorge.lopera
Thanks john for the inlet/outlet advice.

At my model If I defined the model without Initial Volume, for example, All Fea part with volume filled, how I define the Initial Volume?


Do you where do I found samples about it?

Thanks
Technical Specialist
Nexsys de Colombia
Please use plain text.
Active Contributor
jorge.lopera
Posts: 35
Registered: ‎09-21-2006

Re: OPEN CHANNEL ANALYSIS - Results Interpretation

12-05-2012 06:19 AM in reply to: jorge.lopera

I attached the model that I want to calculate the time to drain....

 

Imagine all the solid filled with water....

Technical Specialist
Nexsys de Colombia
Please use plain text.
Valued Mentor
AstroJohnPE
Posts: 494
Registered: ‎08-30-2012

Re: OPEN CHANNEL ANALYSIS - Results Interpretation

12-05-2012 09:32 AM in reply to: jorge.lopera

From looking at the "Getting Started > Help > Tutorials" command, I do not see any tutorials for the Open Channel Flow analysis type. Perhaps one of the other readers has created an open channel flow model example/tutorial and can share it.

 

For setting the initial fluid volume, my suggestion is to go to "Getting Started > Help > Online Wiki Help" and type "initial volume" in the search box. This will lad you to the page titled Initial Fluid Volume which describes the procedure.

 

John Holtz, PE
Mechanical Engineer
Pittsburgh, PA

16 years experience with Simulation Mechanical
Please use plain text.