We evaluate the applicability of a production computational fluid dynamics code for conducting detached eddy simulation for unsteady flows. A second-order accurate Navier-Stokes code developed at NASA Langley Research Center, known as TLNS3D, is used for these simulations. We focus our attention on high Reynolds number flow (Re = 5× 10 − 1.4× 10) past a circular cylinder to simulate flows with ...

in this paper it is attempted to investigate the behavior of an inviscid flow in the meridional plane of an axial flow compressor. for this purpose the 3-d unsteady euler equations in cylindrical coordinate are averaged in tangential direction. therefore, the equations are reduced to a 2-d system. by averaging the tangential component of momentum equation, a blade force will result. axial and r...

The present investigation examines the suppression of unsteady, two-dimensional wake instabilities of a pair of identical circular cylinders, placed side-by-side normal to freestream at a low Reynolds number of 150. It is found that when the cylinders are counter-rotated, unsteady vortex wakes can be completely suppressed. At fast enough rotational speeds, a virtual elliptic body is produced by...

Compressible large-eddy simulations of turbulent flow over a wall-mounted hump with active flow control are performedand comparedwithprevious experiments. Theflow is characterizedby the unsteady separationbefore the steep trailing edge, which naturally reattaches downstream of the hump to form an unsteady turbulent separation bubble. The lowMachnumber large-eddy simulation demonstrated a goodpr...

Front propagation in two-dimensional steady and unsteady cellular flows is investigated in the limit of very fast reaction and sharp front, i.e., in the geometrical optics limit. For the steady flow, a simplified model allows for an analytical prediction of the front speed v f dependence on the stirring intensity U , which is in good agreement with numerical estimates. In particular, at large U...

Vector fields are a common concept for the representation of many different kinds of flow phenomena in science and engineering.Methods based on vector field topology have shown their convenience for visualizing and analyzing steady flow but a counterpart for unsteady flow is still missing. However, a lot of good and relevant work has been done aiming at such a solution. We give an overview of t...

Computational results are presented for the unsteady flow in a powered Hartmann resonance tube. The results were obtained using the WIND code for the two dimensional viscous flow in a five-block solution domain that includes the CD nozzle supplying the jet to the closed end tube within the ambient surrounding. The computed results are presented for the unsteady flow mechanisms involved in the r...

The unsteady, incompressible boundary layer flow caused by an impulsively stretching surface under the influence of a transverse magnetic field is investigated. The partial differential equations governing the laminar flow, under boundary-layer approximations, are non-dimensionalised using similarity transformations and then solved numerically using an efficient, implicit finite-difference sche...

Statistical flow modelling does not provide enough detail for many flows of engineering relevance in which unsteadiness is a central feature. This applies particularly to bluff-bodies and assemblies comprising bluff components for which the resolution of peak forces, unsteady loading, acoustics and fatigue are of interest as part of the design process. An example application which has been stud...

System identification is evaluated as an efficient and accurate technique for modeling unsteady aerodynamic forces for use in time-domain aeroelastic analysis. In the system identification methodology, the constant coefficients of a linear system model are fit to the computed response time histories from a 3-D, unsteady CFD solver. The resulting model of the unsteady CFD solution is independent...