Stabilization of crossflow instability with plasma actuators: Linearized Navier-Stokes simulations

TL;DR

This study investigates using plasma actuators to control crossflow vortices and delay transition in boundary layers, combining linearized Navier-Stokes simulations with experimental validation, revealing complex unsteady effects.

Contribution

It introduces a linearized Navier-Stokes modeling approach for plasma actuator control of crossflow vortices, validated against experiments, highlighting challenges from actuator unsteadiness.

Findings

Good agreement between LNS simulations and experiments on mode amplitudes.

Numerical models suggest transition delay, but experiments show transition advance.

Actuator-induced unsteadiness affects control effectiveness in practice.

Abstract

This paper describes work carried out within the European Union (EU)-Russia Buterfli project to look at the control of transition-causing "target" stationary cross flow vortices, by the use of distributed plasma actuation to generate sub-dominant "killer" modes. The objective is to use the "killer" modes to control the "target" modes through a non-linear stabilizing mechanism. The numerical modelling and results are compared to experimental studies performed at the TsAGI T124 tunnel for a swept plate subject to a favorable pressure gradient flow. A mathematical model for the actuator developed at TsAGI was implemented in a linearized Navier Stokes (LNS) solver and used to model and hence predict "killer" mode amplitudes at a measurement plane in the experiment. The LNS analysis shows good agreement with experiment, and the results are used as input for non-linear PSE analysis to predict the effect of these modes on crossflow transition. Whilst the numerical model indicates a delay in transition, experimental results indicated an advance in transition rather than delay. This was determined to be due to actuator induced unsteadiness arising in the experiment, resulting in the generation of travelling crossflow disturbances which tended to obscure and thus dominate the plasma stabilized stationary disturbances.