PhD Thesis - staffweb - University of Greenwich

APPENDIX 1 : SMARTFIRE VERIFICATION AND VALIDATION REPORTIn Figure 11 the reattachment point is denoted by P and the distance from the step to point Pis s. The ratio of s to the height of the step (h) predicted by the following CFD codes areSMARTFIRE: 5.70; PHOENICS: 6.55; FLOW3D: 5.16. Experimental results indicates thatthe ratio is 7.1 [1, 2]All three codes predict values for the reattachment point that are similar and all codesunder-predict the correct value. The SMARTFIRE prediction falls between that ofPHOENICS and FLOW3D. It is expected that these values will improve with further meshrefinement.Velocity profilesIn addition to the reattachment distance, it is also important to compare the prediction of thevelocity profile at several locations within the duct. In this case, the SMARTFIRE,PHOENICS and FLOW3D generated U velocity profile at the outlet and 0.285 m from theinlet are compared. U velocity profiles for this case at the two different positions arepresented below in Figure 12 and Figure 13.12U (m/s)U velocity at outlet10864smfphoenicsflow3d200 0.02 0.04 0.06 0.08 0.1 0.12Figure 12 - U velocity against height at the outlet.distance from the lower wall (m)Appendix 11.1 Page 141-13 13