[Top][All Lists]

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [ff3d-users] Problem with setting Boundary condition

From: Stephane Del Pino
Subject: Re: [ff3d-users] Problem with setting Boundary condition
Date: Sat, 17 Apr 2010 17:55:37 +0200
User-agent: KMail/1.12.4 (Linux/2.6.32-3-amd64; KDE/4.3.4; x86_64; ; )

Le vendredi 16 avril 2010, Juzar Thingna a écrit :
> I want to set the derivative of w along the y-direction to be equal to wb
>  at ymin. I thought that setting dnu(w)=wb would do the trick, but
>  apparently I don't get the value of the slope at ymin = wb.
> Please could someone guide me as in where I'm going wrong?
> The foll is my geometry file:
> box {<0,7,0>,<20,37,20> pigment{color rgb <1,0,0>}}
> Regards,
> Juzar Thingna
> Center for Computation Science and Engineering
> National University of Singapore


dnu(u) is not the normal derivative of "u" but the co-normal derivative as 
described in remark 14 of the user documentation (p50).
Your pde is 
so the co-normal derivative is :
        dnu(w) = -L*dn(u)
where I noted here dn(u) to be the normal derivative. So, to get 
you need to specify
        dnu(w) = -wb/L

This is quite tricky ... To really understand how to set dnu(w) you need to 
understand variational formulas ...

Best regards,

reply via email to

[Prev in Thread] Current Thread [Next in Thread]