On the application of statistical turbulence models to the simulation of airflow inside a car cabin

Abstract

Computational fluid dynamics simulations of airflow inside a full-scale passenger car cabin are performed using the Reynolds averaged Navier–Stokes equations. The performance of a range of turbulence models is examined by reference to experimental results of the streamwise mean velocity and turbulence intensity profiles, obtained using the hot-wire anemometry technique at different locations inside the car cabin. The models include three linear eddy-viscosity-based variants, namely, the realizable k– ε, the renormalization group k– ε, and the shear-stress transport k– ω models. The baseline Reynolds stress model (BSL-RSM), a second-moment-closure variant, and an Explicit Algebraic Reynolds Stress Model (BSL-EARSM) are also investigated. Visualization of velocity vectors and streamlines in different longitudinal planes shows a similar airflow pattern. The flow topology is mainly characterized by jet flows developing from the dashboard air vents and extending to the back-seats compartment resulting in a large vortex structure. Additionally, a comparison between numerical and experimental results shows a relatively good agreement of the mean velocity profiles. However, all models exhibit some limitations in predicting the correct level of turbulence intensity. Moreover, the realizability of the modeled Reynolds stresses and the structure of turbulence are analyzed based on the anisotropy invariant mapping approach. All models reveal a few amounts of non-realizable solutions. The linear eddy-viscosity-based models return a prevailing isotropic turbulence state, while the BSL-RSM and the BSL-EARSM models display pronounced anisotropic turbulence states.

Experimental and numerical characterization of the airflow in the wake of a heavy truck

“…They also appear to return realizable solutions of the Reynolds stress components and allow capturing the anisotropic structure of the turbulence. 45 Note that two other models of closures have been considered, a second-moment closure-based model namely the x-Reynolds stress model, and also an algebraic Reynolds stress model namely the explicit algebraic Reynolds stress model (EARSM). However, in the following, we will not present them for the sake of clarity and because the results obtained are not much different, especially compared to the BSL-RSM model.…”