PURPOSE This study aims to present flow control over the backward-facing step with specially designed right-angle-shaped plasma actuator and analyzed the influence of various scales of flow structures on the Reynolds stress through snapshot proper orthogonal decomposition (POD). METHODS 2D particle image velocimetry measurements were conducted on region (x/h = 0-2.25) and reattachment zone in...

A Galilean invariant weak-equilibrium hypothesis that is sensitive to streamline curvature is proposed. The hypothesis leads to an algebraic Reynolds stress model for curved ows that is fully explicit and self-consistent. The model is tested in curved homogeneous shear ow: the agreement is excellent with Reynolds stress closure model and adequate with available experimental data. This research ...

In this research the separation efficiency of deoiling hydrocyclone is evaluated using three-dimensional simulation of multiphase flow based on Eulerian-Eulerian finite volume method. The mixture approach of Reynolds Stress Model is also employed to capture the features of turbulent multiphase swirling flow. The obtained separation efficiency of Colman's design is compared with available experi...

A new wall model for LES is proposed. Unlike conventional zonal approaches, given Reynolds stresses are not imposed as the solution, but used as constraints on the SGS stress so that the given Reynolds stress closely matches the computed one only in the mean sense. Also, since LES in general outperforms RANS even at coarse resolution except very near the wall, RANS constraints are limited to th...

Separation of suspended droplets in a fluid flow has been a great concern for scientists and technologists. In the current study, the effect of the surface roughness on flow field and the performance of a gas-oil cyclone is studied numerically. The droplets and the turbulent airflow inside the cyclone are considered to be the discrete and continuous phases respectively. The Reynolds stress mode...

The purpose of this work is to compare di erent low-Reynolds-number turbulence models and their suitability for the highly three dimensional return channel with a deswirl cascade. A comparison is made between Chien's k model, Chien's model with a rotational correction, Gatski et al. ARSM and the full Reynolds stress model by Speziale et al.. Experiments are provided by Concepts ETI. MAIN RESULT...

A formulation to include the e ects of wall proximity in a second moment closure model that utilizes a tensor representation for the redistribution terms in the Reynolds stress equations is presented The wall proximity e ects are modeled through an elliptic relaxation process of the tensor expansion coef cients that properly accounts for both correlation length and time scales as the wall is ap...

We re-examine the Boussinesq hypothesis of an effective turbulent viscosity within the context of simple closure considerations for models of strong magnetohydrodynamic turbulence. Reynolds-stress and turbulent Maxwell-stress closure models will necessarily introduce a suite of transport coefficients, all of which are to some degree model-dependent. One of the most important coefficients is the...

Four classes of turbulence models (algebraic, k − , k − ω and a differential Reynolds-stress model) are applied to boundary layers under adverse pressure gradient with a constant equilibrium parameter β = δ * τ w dp dx. Numerical solutions up to Re θ = 10 8 give the classical scalings in the inner and outer layer for all models. Comparison is made with experiments of Clauser at β ≈ 2 and 8 and ...