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Problem in generating linear Wave !?

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Old   November 29, 2012, 04:05
Default Problem in generating linear Wave !?
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hoannv
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Dear all,
I am trying to generate linear Wave in CFX,..
I all so make following conditions:
@Inlet : i applied velocity at Ui and Vi ; and Fluid Values: water= WaterI
@Outlet: Relative Pressuer is Hypers, Fluid value is Zero gradient
WaterI = if(y<WaterSurface, 1, 0)
Hypres= if(y >WaterSurface, 0[Pa], (997-1.185)*g*(WaterSurface-y))
WaterSurface = 0,5*H*Cos(2*pi*(x/L-t/T))
Ui = pi*H /T *cosh(2*pi*(y+d)/L )*cos(2*pi*(x/L -t/T))/cosh(2*pi*d/L )
Vi = pi*H /T *sinh(2*pi*(y+d )/L )*sin(2*pi*(x/L -t/T))/sinh(2*pi*d /L )

H: wave height
L: wave length
T wave period
d: mean water depth


But, my result is non-reasonable,... Pls ponit me what is wrong ?

thank and sorry for my English
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Old   November 29, 2012, 17:20
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Glenn Horrocks
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If you want us to help you, you will have to describe what happened. What is not reasonable about it?
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Old   November 29, 2012, 21:33
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Quote:
Originally Posted by ghorrocks View Post
If you want us to help you, you will have to describe what happened. What is not reasonable about it?
Frist of all, i am wondering my applied boundary conditions right or wrong for linear wave ?
Followings describes my problem, The result is nonreasonable and i dont understand it

pls let me know what is wrong here !

Many thank and Brg
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Old   November 30, 2012, 11:20
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First seems like you didnt initialise the model. For 2-Phase transient flow it is necessary to define the area of water before the simulation. I did this 2D numerical wave channel thing in Fluent a couple of years ago, so the main problem is not to generate the waves, it is to get the waves out of the model. Fluent supported this with sth called numerical beach treatment, maybe you have similar functions in CFX. No ideas if your formulas are right but you have to differentiate between shallow and deep water waves, which you will find with the right formulars in every good book about free surface/open channel flow
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Old   December 3, 2012, 23:13
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Quote:
Originally Posted by PeMo View Post
First seems like you didnt initialise the model. For 2-Phase transient flow it is necessary to define the area of water before the simulation. I did this 2D numerical wave channel thing in Fluent a couple of years ago, so the main problem is not to generate the waves, it is to get the waves out of the model. Fluent supported this with sth called numerical beach treatment, maybe you have similar functions in CFX. No ideas if your formulas are right but you have to differentiate between shallow and deep water waves, which you will find with the right formulars in every good book about free surface/open channel flow
Dear Pemo and all, i also define the initialisation for each phase by Waterini expression... and i try to make another example by following attackment, file CFD-Online.ccl, but when i run it... the error "Floating point" is occured
Imagine define my model, CFD-Online.ccl define boundary condition i made... pls see and correct it

Thank so much !
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