Unreasonable res0Norm

[nkulkar2]

Hello,

I am trying to setup a turbulent case and solving for the temperature equation. But I am facing unreasonable res0Norm error. The case works when I remove temperature from the *.par file. My *.par file and the useric and userbc are shown below:

[GENERAL]
stopAt = endTime
#numStep = 0
endTime = 200.0
dt = 1e-03
variableDt = yes
timeStepper = bdf2
writeControl=runTime
writeInterval=5.0

regularization = hpfrt + nModes=1 + scalingCoeff=10

polynomialOrder = 7
#startFrom = channel0.f00003

[PRESSURE]
residualTol = 1e-05
residualProj = no

[VELOCITY]
residualTol = 1e-07
density = 1.0
viscosity = -10000
residualProj = no

[TEMPERATURE]
#ConjugateHeatTransfer = no
##advection = yes
conductivity = -8590.0
rhoCp = 1.0
residualTol = 1.0e-6

c-----------------------------------------------------------------------
subroutine userbc(ix,iy,iz,iside,ieg) ! set up boundary conditions
c NOTE ::: This subroutine MAY NOT be called by every process

  implicit none

  integer ix,iy,iz,iside,ieg

  include 'SIZE'
  include 'TOTAL'
  include 'NEKUSE'

  real uin, vin, win
  integer e
  common /cvelbc/ uin(lx1,ly1,lz1,lelv)
 $              , vin(lx1,ly1,lz1,lelv)
 $              , win(lx1,ly1,lz1,lelv)

  if (ifield.eq.1) then ! velocity field
    e = gllel(ieg)
    ux=uin(ix,iy,iz,e)
    uy=vin(ix,iy,iz,e)
    uz=win(ix,iy,iz,e)
  elseif (ifield.eq.2) then ! temperature field
	 temp=1.0
  else
    write(6,*) 'ifield index is larger than the number of '
    write(6,*) 'fields set to 1 '
    call exitt()
  endif
  return
  end

c-----------------------------------------------------------------------
SUBROUTINE USERIC (IX,IY,IZ,ieg)

C Set user-defined initial conditions

  implicit none

  integer ix,iy,iz,ieg

  INCLUDE 'SIZE'
  INCLUDE 'TOTAL'
  INCLUDE 'NEKUSE'
  
  real bpara,apara,kx,kz,eps

  eps = 1e-2
  kx  = 23
  kz  = 13

  apara = kx * 2*PI/10
  bpara  = kz * 2*PI/10

  if (ifield.eq.1) then ! velocity field
	  ux=0.0 + eps*bpara  * sin(apara*x)*cos(bpara*z)
	  uy=1.0 + eps*bpara  * sin(apara*x)*cos(bpara*z)
	  uz=0.0 - eps*bpara  * sin(apara*x)*cos(bpara*z)
  elseif (ifield.eq.2) then ! temperature field
	  temp=1.0
  else
    write(6,*) 'ifield index is larger than the number of '
    write(6,*) 'fields set to 2 '
    call exitt()
  endif
  RETURN
  END

c-----------------------------------------------------------------------

How do avoid this error? I changed my initial condition for temp from 0.0 to 1.0 but that didn't help.

Thank you

Nilay

[yslan]

Hi Nilay,

That usually happens if your BC or even vp is not set properly.
It might help if you set verbose = true under the [GENERAL] session and paste the residual and timestep as well.

Note that, the userbc inside the usr file is never called.
You should implement the boundary condition inside the oudf.
The reused BC value uin, vin and win need to be revisited as well.

Yu-Hsiang

[nkulkar2]

Hi Yu-Hsiang,

I applied the userbc and useric for a pipe flow case and it works with a recirculating flow condition and I get the flow profile as expected. And I tried adding verbose = true but the error persists.

Thank you

Nilay