[Nek5000-users] Variable density flows

[nek5000-users at lists.mcs.anl.gov]

You can also try error function like profile with 0 value at the inlet and increases to a peak somewhere and stays constant up to the exit so gradient is0 at the exit
Insulation normally refers to the diffusive flux (first form)
Ammar

Sent from my iPhone

> On Oct 12, 2013, at 11:50 PM, nek5000-users at lists.mcs.anl.gov wrote:
> 
> Yes Ammar, I get oscillatory solutions with the discontinuous bc. I will try your suggestion.
> 
> When we specify insulated bc 'I' for an advected-diffused scalar c, does it make
> 
> grad(c).n = 0 
> 
> or
> 
> (u.n)c - D*grad(c).n = 0
> 
> If I want to implement the second case, what should I do ?
> 
> Thanks
> praveen
> 
> 
> 
>> On Sun, Oct 13, 2013 at 10:11 AM, <nek5000-users at lists.mcs.anl.gov> wrote:
>> The c=0 bc Is not consistent with the initial condition. You are generating a big error at t=0 that persists throughout your simulation. My understanding is you want to simulate the dispersion of a scalar that is already injected in a flow at t=0 right?  I would spatially localize the concentration so that it decays to 0 at the inflow boundary ..a Gaussian exp(- x-a)^2) is a good candidate for your initial conditions 
>> Ammar
> 
> 
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