Numerical Study of Dynamo Action at Low Magnetic Prandtl Numbers

Abstract : We present a three-pronged numerical approach to the dynamo problem at low magnetic Prandtl numbers PM . The difficulty of resolving a large range of scales is circumvented by combining direct numerical simulations, a Lagrangian-averaged model and large-eddy simulations. The flow is generated by the Taylor-Green forcing; it combines a well defined structure at large scales and turbulent fluctuations at small scales. Our main findings are (i) dynamos are observed from PM ≈