# velocity varies with time

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 February 14, 2004, 17:26 velocity varies with time #1 Aly Guest   Posts: n/a Sponsored Links HI, I am doing Design of Breakwaters by Starcd,I am trying to put inlet as Velocity varies with Time, how can I do this, instead of constant velocity?

 February 15, 2004, 11:46 Re: velocity varies with time #2 allan Guest   Posts: n/a either use a table or add user coding in bcdefi.f allan

 February 16, 2004, 03:55 Re: velocity varies with time #3 Richard Guest   Posts: n/a You can use a table or a user subroutine (BCDEFI). Have a look at Chapter 7 of the User Guide.

 February 17, 2004, 09:37 Re: velocity varies with time #4 Aly Guest   Posts: n/a Thanks for Answers, I have looked on chapter 7 & 8 still not solve my problem, I have two set of Data VELLOCITY and TIME, how can I Put these data on the Table of Advanced Transients on page 11 chapter 8 of STAR-G or in other way how can I process this data as inlet (incomming velocity as function of time). thanks Aly

 February 17, 2004, 14:44 Re: velocity varies with time #5 Brian Guest   Posts: n/a To make boundary velocity a function of time, you need to use a table or user coding, as already stated. This has nothing to do with the Advanced Transients input window, shown on page 8-11 of the User Guide. That window is for setting up the timestep and so on of your transient run. You need to set up the table using the table dialogue, and link to it in the boundary definition. See page 2-14 for how to set up tables and page 7-13 for how to activate the table in the boundary condition.

 March 1, 2004, 21:18 Re: velocity varies with time #6 Aly Guest   Posts: n/a I want to input a wave velocity which varies with time by a sunusoidal function [v=sin(wt)]. The questions are: 1- Should I put this as components in x and y for Star-CD to understand or it will understand by itself if I put just (v). 2- If it is x and y, is it realistic to put these as independent variables. Because I only see that option in the star-CD. Thanks.

 March 2, 2004, 04:31 Re: velocity varies with time #7 Jörn Beilke Guest   Posts: n/a Why dont you use the subroutine and put in you formula. It it very easy to do. Just try it. here an example of BCDEFI ..... PI = ACOS(-1.0) IF (IREG.EQ.1) THEN U = 3.0*SIN(2.0*PI*TIME) V = 2.0*COS(3.0*PI*TIME) ENDIF ..... RETURN END U and V are the velocity components, TIME is already available and x,y,z are the global coordinates.

 March 10, 2004, 16:53 Re: BOUNDARY CONDITION #8 chang Guest   Posts: n/a Hi, Iam working with transet problem, Ihave define mdel boundary as this view 0 0 1 replot bzone 1 all view 0 0 -1 replot bzone 1 all rdef 1 symp bset all bdis on view 1 1 1 replot bdis off view 0 0 1 Problem is that Iwant to define other two boundaries Inlet on one face and wall in middle of my model where there is obsticle, How can Ido that? please any one can help? chang

 March 25, 2004, 06:39 Re: BOUNDARY CONDITION #9 Brian Guest   Posts: n/a try using VSET NEWS EDGE and BFIND commands?

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