Bounds error message with no observable effect on simulation
Hi,
In some of my conjugate heat transfer simulations a bounds error is reported at fluid outlet boundary for absolute pressure. However, the simulation converges nicely. ================================================== ==================== OUTER LOOP ITERATION = 288 ( 99) CPU SECONDS = 3.486E+05 (1.191E+05)   Equation  Rate  RMS Res  Max Res  Linear Solution  ++++++  UMom  0.95  8.7E09  2.5E07  3.8E02 OK  VMom  0.95  4.1E09  3.9E07  4.2E02 OK  WMom  0.94  1.7E09  2.0E07  4.4E02 OK  PMass  0.93  2.1E10  1.8E08  9.7 7.5E02 OK ++++++ ++  ****** Notice ******   While evaluating   Total Enthalpy   on boundary "Outlet fluid",   the variable   Absolute Pressure   went outside of its upper limit. Its maximum value was   2.6667E+15. The bounds error was handled by clipping.   If this situation persists, consider increasing the table range.  ++  HEnergy  0.95  9.6E07  6.6E05  9.5E02 OK  TEnergyManifold so  0.99  3.0E09  3.6E08  9.5E02 OK  TEnergyBottom plat  0.99  2.7E09  2.1E08  6.2 9.5E02 OK ++++++ CFD Solver finished: Mon Mar 19 01:08:37 2012 CFD Solver wall clock seconds: 3.1119E+04 ================================================== ==================== Termination and Interrupt Condition Summary ================================================== ==================== CFD Solver: All target criteria reached (Equation residuals AND global imbalances) ================================================== ==================== As I show above the bounds error is reported in even the last iteration before convergence. Now when I plot the absolute pressure on the fluid outlet boundary, everything seems alright ...there are no values of order of 1e15. Any idea why CFX would throw out this message? The mesh is also ok. 
There will be a value of 1e15 somewhere, that is why it is being reported. It is pobably a single node on an outlet, next to the wall or something.

I agree.
But since I cannot spot that value when I analyze the results in CFXpost (even the range of absolute pressure over the entire computational domain is physical i.e. the range of absolute pressures spans in the order of 1e5), so I think my results are OK.Please correct me if I am wrong. But why this value is reported is curious. Sometimes, by changing the timestep the Bounds error message stops. Simulation converges anyhow though to a steady state solution, with or without changing timestep and final results are also same. 
It might be a transitory numerical thing. A small numerical instability is causing that small area of the mesh to go haywire, but it eventually gets over it and converges. If the final solution is properly converged and bounded then I would ignore it. But it does suggest your simulation's numerical stability is marginal.

All times are GMT 4. The time now is 01:27. 