Program EDDYBL

412 APPENDIX D . PROGRAM EDDYBLgram EDDYBL always prints profiles at the final station . Also, wheneverEDDYBL prints profiles, disk file output.dat is automatically written .D.5 .14 Selecting Laminar, Transitional or MurbulentFlowProgram EDDYBL can run in three different modes corresponding to (1)pure laminar flow, (2) transition from laminar to turbulent flow, and (3)pure turbulent flow . The two test cases exercise EDDYBL in its pureturbulent mode in which integral parameters are specified and MOUND isset to 1 .To run in the transitional mode, simply select MOUND = 0 in theInitial Profiles/Integral Parameters menu . As a result, exact laminarvelocity and temperature profiles will be generated in conjunction withapproximate laminar profiles for the various turbulence-model parameters .The actual transition point is determined automatically by the model equationsand depends strongly upon the freestream values of k and w that arespecified in the Main Parameters/ Freestream Conditions menu interms of ZIOTAE and ZIOTAL . To obtain physically realistic transitionReynolds numbers you must include low-Reynolds-number corrections inthe k-w and multiscale models by setting NVISC = 1 in the TurbulenceModel sub-menu . Although the k-c models are capable of predicting transition,extremely small streamwise steps are needed with EDDYBL, andstable computation is very difficult to achieve .Even if you are not interested in transition, this mode is neverthelessuseful as it provides an alternate method for generating turbulent startingprofiles, e.g ., by starting laminar and running up to a desired value of Re o .Finally, to run EDDYBL as a pure laminar boundary-layer program,the turbulence model can be suppressed by setting MODEL to -1 in theTurbulence Model sub-menu . When this is done, turbulence model computationsare bypassed and no transition to turbulence occurs .D .6Applicability and LimitationsProgram EDDYBL applies to attached, compressible, two-dimensionaland axisymmetric boundary layers . The program computes properties ofturbulent boundary layers using the Wilcox (1988a) k-w model or theWilcox (1988b) multiscale model, including effects of surface roughness,surface mass transfer, surface curvature, and low-Reynolds-number corrections. The program also includes several low-Reynolds-number versions ofthe k-c model.