Development of an empirical body force model for plasma-based flow control in CFD applications

Tesis Energía y Ambiente (maestría) - Instituto Tecnológico de Buenos Aires - Karlsruher Institut für Technologie, Karlsruhe, 2020 In the present work a new empirical model for the phase-resolved body forces of an DBD (Dielectric-Barrier-Discharge)-plasma actuator is developed. Therefore planar body forces have been derived from existing PIV (Particle-Image Velocimetry) measurements. A new approach is introduced that makes use of the similarity of fluid dynamic and electrostatic potential theory. The body forces are derived with the gradient of a scalar potential field that consists of superimposed single body force potentials. A system of linear equations describes the relation between the gradient field, the magnitude of the single potentials and the resulting body forces. A least-square fit of this equation system to the experimental body forces approximates the local magnitude of the potentials. The modeling results are compared to the experimental data regarding their phase-averaged and phase-resolved integral body force, the spatial body force distribution and the physical plausibility of the potential magnitudes. Centering around a baseline state, different numeric configurations of the model and their results are presented and discussed. This baseline state strongly indicates the validity of the developed approach, particularly regarding the resulting values of phase-resolved integral body forces. A future improvement of the numeric setup of the model is expected to prove the similarity of the distribution of body force potentials and free charges in the discharge area. This could lead towards a model that is independent from experimental validations. Finally, the new model is drawn into comparison with former modeling approaches by Shyy et al. [28], Suzen et al. [31] and Maden et al. [23]. Here it asserts itself with its unique capability to represent both components of phase-resolved body forces with good accuracy.