Application of the Sensors

For the usage of the sensors in the standard parameter files some variables were added to activate the best practice guidelines, the visual output and warnings.

4.1 Error Sensors

After activation of the best practice output and declaration of the directory contain­ing the configuration files of the best practice guidelines, the functionality of the individual sensors can be switched on and off. The configuration files are necessary to estimate the errors in the friction coefficients depending on the used model. These files contain a parameterized form of the error function as a polynomial 3rd order

(p(x) = a0 + a1x + a2x2 + a3x3) and the range of validity of this function. The func­tion represents the influence of the error on the friction coefficient and is computed by Cf normalized by the friction in the reference grid Cfn = cf /cf, ref. In addition for all errors a warning is given about the resulting influence on the skin friction component of the integral force coefficients. For this the drag coefficient was cor­rected by the resulting error in the friction and integrated along the wall surface. The computed and the corrected coefficients are compared and the result is written as a feedback in the flow solver output in %.

The error output and prediction are available for the turbulence models listed in Section 4.