CFD Online Discussion Forums

CFD Online Discussion Forums (http://www.cfd-online.com/Forums/)
-   CFX (http://www.cfd-online.com/Forums/cfx/)
-   -   Simulation with motion (http://www.cfd-online.com/Forums/cfx/109249-simulation-motion.html)

liuzexiang November 13, 2012 09:47

Simulation with motion
 
hi,i do a simulation that including the electric filed and flow field. the case is the brine flows along the a tube(materical :steel) to a plane(material:steel),and the tool and plane are connected with the direct current power. when the tool is stationary,the silulation is successful. but when the tool domain is set as solid motion,the error is "In Analysis 'Flow Analysis 1' - Domain 'tool solidzone: Solid motion is active and electric or magnetic models have been used. This combination is not supported."
my question is whether the case can be simulate by seting the tool motion?
thank you

ghorrocks November 13, 2012 20:30

The error message is very clear. The answer is no.

liuzexiang November 14, 2012 20:57

hi,ghorrocks,thank you for your reply. i want to know is there any methond to solve this kind of simulation?

ghorrocks November 14, 2012 20:59

There is a small chance there is a beta feature in CFX to allow somethine close to what you want to do. You will have to speak to CFX support for details about the beta features.

Otherwise you will need to go to another code.

liuzexiang November 14, 2012 21:10

hi,ghorrocks,thanks . i will try to find the beta feature in CFX help document.

ghorrocks November 14, 2012 21:19

Few, if any, of the beta features are described in the documentation. You need to talk to CFX support.

liuzexiang November 14, 2012 21:27

hi,ghorrocks, is there any way to talk with CFX support?

ghorrocks November 15, 2012 04:43

Contact the local support representative for ANSYS in your country. Or contact them through www.ansys.com

liuzexiang November 15, 2012 09:25

hi,ghorrocks, thank you for your advice. i will try to connect with che CFX support in china.
i have some difficulties in my simulation. that is :
1. in the simulaton, the temperature in the fludzone is different at different point .how to gain the temperature function of the coordinate the in the fluidzone. does the step function solve this different.
2. about volume fraction. the fuludzone is consisted with liquid and air. i set the initial condition about the volume fraction and gas fraction. but how to gain the function of the volume fraction at different in the coordinate.
as i will use the temperature function and volume function in my next simulation, so i need to know these functions in the coordinate.
thanks

ghorrocks November 15, 2012 16:59

You can extract this in post-processing through CFD-Post, or by monitor points in the solver. This is easy post-processing.

liuzexiang November 15, 2012 20:20

by monitor points just some points ,not all. and i think these function should be established in the CFX-pre,not in cfx-post,because in the simulation the electrical conductivity of the flow is the function of the temperature and the gas volume fraction. the electrical conductivity at different point directly effect the current density in the simulation.

ghorrocks November 16, 2012 05:00

You can use as many monitor points as you like, and if you want the time history set them up in CFX-Pre and as the solution progresses you will get the time history at that point. If you want the entire flow field then save a results file and export it into a format you want.

CFX can do all this easily. Have you looked at what exporting options are available?

And what are you trying to do anyway?

liuzexiang November 18, 2012 05:59

i think setting many monitor points is not a good idea that i can not put them in another function such as y=k*air.volume.fraction at different point. so i find the coordinate function ahout xGloble,yGloble and zGloble in the CFX help,maybe this kind of function solve the problem. but there is no detail. what is the good idea.

ghorrocks November 18, 2012 06:02

Yes, you can use to monitor point point values with the point() function.

But what are you trying to do anyway? What does y=k*air.volume_fraction mean?

liuzexiang November 18, 2012 06:55

i want to use the air.volume fraction() as a variable in the sumulation to compute another function, so the format is y=k*air.volume_fraction()

liuzexiang November 18, 2012 07:56

the electric flow in the simulation contain the gas and conductive fluid , the temperature of the fluid , bubble rate will directly affect the electrical conductivity of the conductive fluid , so I think the temperature of the fluid , bubble as the dependent variable , the conductivity of the fluid is set to change as the function value . However , in the process of setting expression encountered a small trouble : With the coordinate position of the change in the fluid ,the temperature, the bubble rate also changes as the CFX can not use point coordinates (x, y, z) function, thus I assume in the same plane , the temperature and the bubble rate is equate , so the problem is transformed into a function of the position with the height z changed . but how to describe the relation between them. i need your help,thanks !

ghorrocks November 18, 2012 15:50

Why do you need to use a point at all? This sounds like a field function which get evaluated at every point in the field. Then you just call the local value of volume fraction.

liuzexiang November 19, 2012 03:28

yes, it just is a field function. i think i should define a area function along the z axis,then i can gain the gas.volume fraction at the area() region.

ghorrocks November 19, 2012 05:06

Can you explain the equation you are trying to implement? What are the values in it, and what does it achieve?

liuzexiang November 19, 2012 05:26

yes. the complete is k(z)=k0*(1+a*(T(z)-T0)*(1-b(z))),where,k0 and T0 is initialization, and the T(Z) and the b(z) is the temperature function and gas volume fraction function along the z axis respectively.


All times are GMT -4. The time now is 00:53.