Direct numerical simulation of transitional turbulent flow in a closed rotor-stator cavity

The transitional turbulent regime in confined flow between a rotating and a stationary disc is studied using direct numerical simulation. Besides its fundamental importance as a three-dimensional prototype flow, such flows frequently arise in many industrial devices, especially in turbomachinary applications. The present contribution extends the DNS simulation into the turbulent flow regime, to a rotational Reynolds number Re = 3 × 105. An annular rotor-stator cavity of radial extension Δ R and height H, is considered with L = 4.72 (L = Δ R / H) and Rm = 2.33 (Rm = (R1 + R0)/ΔR). The direct numerical simulation is performed by integrating the time-dependent Navier-Stokes equations until a statistically steady state is reached. A three-dimensional spectral method is used with the aim of providing both very accurate instantaneous fields and reliable statistical data. The instantaneous quantities are analysed in order to enhance our knowledge of the physics of turbulent rotating flows. Also, the results have been averaged so as to provide target turbulence data for any subsequent modelling attempts at reproducing the flow.