Summary of the 2004 CFD Validation Workshop on Synthetic Jets and Turbulent Separation Control

Abstract

A CFD validation workshop for synthetic jets and turbulent separation control (CFD-VAL2004) was held in Williamsburg, Virginia in March 2004. Three cases were investigated: synthetic jet into quiescent air, synthetic jet into a turbulent boundary layer cross ow, and ow o ver a hump model with no-ow-control, steady suction, and oscillatory control. This paper is a summary of the CFD results from the workshop. Although some detailed results are shown, mostly a broad viewpoint i s t a k en, and the CFD stateof-the-art for predicting these types of ows is evaluated from a general point of view. Overall, for synthetic jets, CFD can only qualitatively predict the ow p h ysics, but there is some uncertainty regarding how to best model the unsteady boundary conditions from the experiment consistently. As a result, there is wide variation among CFD results. For the hump ow, CFD as a whole is capable of predicting many of the particulars of this ow provided that tunnel blockage is accounted for, but the length of the separated region compared to experimental results is consistently overpredicted.

Numerical investigation of the influence of nozzle geometrical parameters on thrust of synthetic jet underwater

“…At the same time, RANS simulation combined with adequate turbulence models such as the k-w SST turbulent model could provide reasonably good solutions [34].…”

Assessment of an approach to generating inflow synthetic turbulence for large eddy simulations of complex turbulent flows

“…The §ow over a 2D wall-mounted hump has been studied in the experiments [7] and widely used as a validation test for turbulence modeling approaches [8]. Scheme of the §ow is shown in Fig.…”

“…Upper wall is slippery and slightly adjusted to account for partial blockage e¨ect as recommended in [8]. The computational domain extends from x/c = −2.14 to 4.0.…”

“…An objective of the present study is a more extensive validation of the method in the framework of zonal RANS LES computations of complex turbulent §ows. These include an aerodynamic §ow with pressure induced separation and reattachment (the wall-mounted hump studied in the experiments [7] and used as a test case in many validation studies, e. g., [8]) and a hydrofoil trailing edge §ow with shallow separation investigated in the experiment [9] and used for validation of di¨erent hybrid RANS LES approaches in the EU project DESider [10].…”

Effects of a synthetic jet acting on a separated flow over a hump

“…In these simulations, however, only simple flow geometries have been analysed; hence, neither the interaction with the cross-flow nor the effects on the over-all aerodynamic performance have been studied. For more practical flow configurations, Reynolds-averaged Navier-Stokes approaches have been taken, and the flow near the injector slot has been solved using unstructured grids (several studies are summarized in Seifert, Theofilis &Joslin 2002 andRumsey et al 2004). Although aerodynamic performance has been predicted in these studies, they have not focused on the dependence on the actuation parameters nor the mechanisms of separation control.…”