Hi, Ashok

I checked the code and find that m_epsilon is not multiplied to diffusion term in this function: 

void Nektar::UnsteadyAdvectionDiffusion::DoOdeRhs(const Array<OneD, const Array<OneD, NekDouble > > & inarray,

Array< OneD, Array< OneD, NekDouble > > & outarray, const NekDouble time)

in file "UnsteadyAdvectionDiffusion.cpp". This is equivalent to set epsilon to 1, so I think you are right.

I added a new line between line 273 and 274 to multiply m_epsilon to diffusion term, like this

272             for (int i = 0; i < nVariables; ++i)

273             {

274                 Vmath::Smul(nSolutionPts, m_epsilon, &outarrayDiff[i][0], 1,

275                             &outarrayDiff[i][0], 1);

276                 Vmath::Vadd(nSolutionPts, &outarray[i][0], 1,

277                             &outarrayDiff[i][0], 1, &outarray[i][0], 1);

278             }

and the code returns right results.

Ankang

-----原始邮件-----
发件人:"ashok jallepalli" <ash.nani@gmail.com>
发送时间:2017-09-03 13:37:51 (星期日)
收件人: "Ankang Gao" <gaoak@pku.edu.cn>
抄送: nektar-users <nektar-users@imperial.ac.uk>
主题: Re: [Nektar-users] ADRSolver epsilon value defaults to 1.0

Thanks Ankang for looking into the issue,

      I have removed the variable epsilon in line 56. The results still have a probelm.

changed to

 55     <FUNCTION NAME="ExactSolution">

 56          <E VAR="u" VALUE="exp(-2.0*FinTime)*sin(x)*sin(y)" />

 57        </FUNCTION>"

The error result are same for epsilon values 1.0, 0.5 and 0.01. I have also attached result for .vtu file of the result (which is same for all the three values of epsilon). The highest value = 0.019 /approx e^(-2.0*2*1.0).

Results

Writing: "P4_codesquare11_2.chk" (0s, XML)

Time-integration  : 145.194s

Writing: "P4_codesquare11.fld" (0s, XML)

-------------------------------------------

Total Computation Time = 149s

-------------------------------------------

L 2 error (variable u) : 0.148193

L inf error (variable u) : 0.018095

Cheers,

Ashok.

On Sat, Sep 2, 2017 at 10:48 PM, Ankang Gao <gaoak@pku.edu.cn> wrote:

Hi, Ashok

There is a typing error in your file Conditions_unsteadyConvectionDom.xml in line 56,

you type "epsion" there instead of "epsilon", this may be the reason.

Ankang

-----原始邮件-----
发件人:"ashok jallepalli" <ash.nani@gmail.com>
发送时间:2017-09-03 12:05:25 (星期日)
收件人: nektar-users <nektar-users@imperial.ac.uk>, "<nektar-developers@sci.utah.edu>" <nektar-developers@sci.utah.edu>
抄送:
主题: [Nektar-users] ADRSolver epsilon value defaults to 1.0

Hi All,

      I am trying to use ADR solver to run unsteady-advection diffusion reaction with epsilon value set to 0.01. But the simulation always defaults to 1.0.

I changed epsilon value to 1.0,0.5 0.01. The end result is always the same (as if epsilon=1.0). Please let me know if anyone has encountered this issue or knows how to fix this bug.

I have added the script files to reproduce this issue.

Cheers,

Ashok.