ask Residual graph sudden increase in the middle of computation in ANSYS FLUENT 17.2

- March 18, 2019 at 3:17 am
  
  teguhhady
  Subscriber
  
  Dear all,
  
  I am simulating heat transfer in turbulent plain straight tube. length of the pipe is 3 m. Inlet: velocity Inlet, Outlet: Outflow, wall: constant temperature. While running the simulation I get sudden increase in residual graph then the residual graph decreases slowly (finally converged). What does it mean? Is my solution is ok because residual get converged in the end of simulation?
  
  PS.I attach the residual graph
- March 18, 2019 at 9:40 am
  
  Amine Ben Hadj Ali
  Ansys Employee
  
  You can ignore it and stick to the fllux omblances from Flux Report as well as monitor key global quantities to judge convergence. The increase might be due to some pressure/density range treatment as you are using outflow boundary conditions.