| Popis: |
This contribution describes the development and evaluation of a new statistical modeling approach for active vortex generator jet (VGJ) flow control. Previous experiments from Technical University Braunschweig, Germany, and a previous evaluation of the experiments by the authors showed that the resulting experimental vortices can be represented by Lamb-Oseen vortices. Based on that, an analytical expression is derived for the maximum circulation V max for the VGJ vortex in terms of the VGJ diameter Φ VGJ, the jet to free stream velocity ratio A, as well as the VGJ pitch and skew angle α and β, respectively. Ymax is used for describing the additional vortex velocity field that is originating from the VGJ. The idea behind the statistical modeling approach is that the generated vortices are represented by their averaged velocity correlations, or vortex stresses, that are in turn added to the transport equations in a Reynolds stres turbulence model. The spanwise averaged vortex stresses are derived by computing the spanwise averaged second-order statisitcs of the flow field. These results are compared to the spanwise averaged vortex stresses from experiments and corresponding results from fully resolved computational fluid dynamics investigations. |
