Implementation of the Boundary Layer Sensor

For the implementation of this sensor again the boundary layer has to be scanned to identify their thickness and the number of wall normal grid points. As the investiga­tions show the choice of the turbulence model itself is an uncertainty. Depending on the model the boundary layer thickness or the friction is differing to each other. The greatest problem is the difference in the gradients of the various values especially the friction coefficient. The reason for this is the calibration of the models and their

Implementation of the Boundary Layer Sensor

Fig. 8 Flat plate — influence of the grid expansion ratio on the prediction of the friction coefficient Cf, normalized with Cf of the reference grid with Menter SST, SAE, SAO, Wallin & Johansson EARSM, RQEVM and LEA model

different development of the boundary layer. Hence it is impossible to give a correct prediction for a local error. Despite that the sensor gives feedback to the user about the boundary layer thickness and the applied grid resolution.