Hi All, i am runing simple case at Re1000, i tried many meshs all of them give me the same error ////////////////////// Steps: 91200 Time: 424.694 CPU Time: 4.48716s Steps: 91210 Time: 424.695 CPU Time: 4.62339s *CG iterations made = 5001 using tolerance of 1e-09 (error = nan, rhs_mag = inf)* *job ended at* ///////////////////////////// any suggestions? my case file /////////////////////////////////////////// <?xml version="1.0" encoding="UTF-8" ?> <NEKTAR> <EXPANSIONS> <E COMPOSITE="C[1]" NUMMODES="6" FIELDS="u,v,w,p" TYPE="MODIFIED" /> <!-- 1 Domain inlet plate upper --> <E COMPOSITE="C[2]" NUMMODES="6" FIELDS="u,v,w,p" TYPE="MODIFIED" /> <!-- 2 Domain inlet plate lower --> <E COMPOSITE="C[3]" NUMMODES="6" FIELDS="u,v,w,p" TYPE="MODIFIED" /> <!-- ****3 Domain square faces up down front meshs**** --> <E COMPOSITE="C[4]" NUMMODES="6" FIELDS="u,v,w,p" TYPE="MODIFIED" /> <!-- 4 Domain upper domain lower in up stream --> <E COMPOSITE="C[5]" NUMMODES="6" FIELDS="u,v,w,p" TYPE="MODIFIED" /> <!-- 5 Domain upper lower downstream --> <E COMPOSITE="C[6]" NUMMODES="6" FIELDS="u,v,w,p" TYPE="MODIFIED" /> <!-- ***6 Domain down stream back side square*** --> <E COMPOSITE="C[7]" NUMMODES="6" FIELDS="u,v,w,p" TYPE="MODIFIED" /> <!-- 7 Domain down stream after square big one --> <E COMPOSITE="C[8]" NUMMODES="6" FIELDS="u,v,w,p" TYPE="MODIFIED" /> <!-- 7 Domain down stream after square big one --> </EXPANSIONS> <CONDITIONS> <SOLVERINFO> <I PROPERTY="SOLVERTYPE" VALUE="VelocityCorrectionScheme"/> <I PROPERTY="EQTYPE" VALUE="UnsteadyNavierStokes" /> <I PROPERTY="Projection" VALUE="Continuous" /> <I PROPERTY="EvolutionOperator" VALUE="Nonlinear" /> <I PROPERTY="TimeIntegrationMethod" VALUE="IMEXOrder2" /> <I PROPERTY="Driver" VALUE="Standard" /> <I PROPERTY="HOMOGENEOUS" VALUE="1D" /> <I PROPERTY="AdvectionForm" VALUE="SkewSymmetric" /> <I PROPERTY="Extrapolation" VALUE="Standard" /> <I PROPERTY="USEFFT" VALUE="FFTW" /> <I PROPERTY="DEALIASING" VALUE="ON" /> <!-- <I PROPERTY="SpectralVanishingViscosity" VALUE="True" /> --> </SOLVERINFO> <PARAMETERS> <P> TimeStep = 0.0001 </P> <P> NumSteps = 2500000 </P> <!-- 500000 250sec --> <P> IO_CheckSteps = 5000 </P> <!-- 120 check files--> <P> IO_InfoSteps = 10 </P> <P> Re = 200 </P> <P> Kinvis = 1./Re </P> <P> IO_CFLSteps = 50 </P> <P> LZ = 9 </P> <!-- 3. * Fastest spanwise --> <P> HomModesZ = 32 </P> <!-- how many cells for Z direction --> </PARAMETERS> <VARIABLES> <V ID="0"> u </V> <V ID="1"> v </V> <V ID="2"> w </V> <V ID="3"> p </V> </VARIABLES> <BOUNDARYREGIONS> <B ID="0"> C[9] </B> <!-- Inlet1_upper --> <B ID="1"> C[10] </B> <!-- Inlet2_Lower --> <B ID="2"> C[11] </B> <!-- Splitter plate --> <B ID="3"> C[12] </B> <!-- Upper Boundary --> <B ID="4"> C[13] </B> <!-- Lower_Boundary --> <B ID="5"> C[14] </B> <!-- Outlet --> <B ID="6"> C[15] </B> <!-- Wall_square --> </BOUNDARYREGIONS> <BOUNDARYCONDITIONS> <REGION REF="0"> <!-- Inlet_upper --> <D VAR="u" VALUE="5" /> <D VAR="v" VALUE="0" /> <D VAR="w" VALUE="0" /> <N VAR="p" USERDEFINEDTYPE="H" VALUE="0"/> </REGION> <REGION REF="1"> <!-- Inlet_lower --> <D VAR="u" VALUE="1" /> <D VAR="v" VALUE="0" /> <D VAR="w" VALUE="0" /> <N VAR="p" USERDEFINEDTYPE="H" VALUE="0"/> </REGION> <REGION REF="2"> <!--Splitter plate --> <D VAR="u" VALUE="0" /> <D VAR="v" VALUE="0" /> <D VAR="w" VALUE="0" /> <N VAR="p" USERDEFINEDTYPE="H" VALUE="0" /> </REGION> <REGION REF="3"> <!-- Upper Boundary --> <N VAR="u" USERDEFINEDTYPE="H" VALUE="0" /> <D VAR="v" VALUE="0" /> <N VAR="w" USERDEFINEDTYPE="H" VALUE="0" /> <N VAR="p" USERDEFINEDTYPE="H" VALUE="0" /> </REGION> <REGION REF="4"> <!-- Lower_Boundary --> <N VAR="u" USERDEFINEDTYPE="H" VALUE="0" /> <D VAR="v" VALUE="0" /> <N VAR="w" USERDEFINEDTYPE="H" VALUE="0" /> <N VAR="p" USERDEFINEDTYPE="H" VALUE="0" /> </REGION> <REGION REF="5"> <!-- Outlet BC --> <N VAR="u" USERDEFINEDTYPE="HOutflow" VALUE="0" /> <N VAR="v" USERDEFINEDTYPE="HOutflow" VALUE="0" /> <N VAR="w" USERDEFINEDTYPE="HOutflow" VALUE="0" /> <D VAR="p" USERDEFINEDTYPE="HOutflow" VALUE="0" /> </REGION> <REGION REF="6"> <!-- WallA_square --> <D VAR="u" VALUE="0" /> <D VAR="v" VALUE="0" /> <D VAR="w" VALUE="0" /> <N VAR="p" USERDEFINEDTYPE="H" VALUE="0" /> </REGION> </BOUNDARYCONDITIONS> <!-- We initialise from pre-computed flow for speed --> <FUNCTION NAME="InitialConditions"> <E VAR="w" VALUE="awgn(1e-3)*cos(2*PI*z/LZ)" /> <!-- <F VAR="u,v,p,w" FILE="SquareN3D_179.chk" /> --> <!-- <E VAR="u,v,w,p" VALUE="0" /> --> <F VAR="u,v,p" FILE="SquareN2D_200.chk" /> <!-- start from 2D results --> </FUNCTION> <FUNCTION NAME="ExactSolution"> <E VAR="u" VALUE="0" /> <E VAR="v" VALUE="0" /> <E VAR="w" VALUE="0" /> <E VAR="p" VALUE="0" /> </FUNCTION> </CONDITIONS> <FILTERS> <FILTER TYPE="AeroForces"> <PARAM NAME="OutputFile">stats/stats1/CylinderForces3D</PARAM> <PARAM NAME="OutputFrequency">10</PARAM> <PARAM NAME="Boundary"> B[6] </PARAM> </FILTER> </FILTERS> </NEKTAR> ///////////////////////////////// please help me in this Regrads, cheers, Reda PhD student Aerospace department UPC Barcelona