Oscillatory compressible flow around a cylinder

Shang, J. S.

doi:10.2514/6.1982-98

Cited by 20 publications

(5 citation statements)

References 15 publications

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“…Such programs have been developed by Erdos and Alzner L1977), Krammer (1982), Ko a and Kotake (1985), Rai (1985Rai ( ), ourmaux (1986 and Giles (198 7). In addition Scott and Hankey (1985a, 1985b modified the program developed by Shang (1982Shang ( , 1983, and Mitchell (1980) and Hodson (1983Hodson ( , 1984) modified Denton's program (initially published in (Denton, 1975)) to solve for unsteady flows. Giles' (1987) program which is called UNSFLO, was used in this study because it is the only one that can handle arbitrary values of R with reasonable CPU and storage requirements due to a novel "tilting" of the time frame.…”

Section: The Computer Programmentioning

confidence: 99%

On the Prediction of Unsteady Forces on Gas-Turbine Blades: Part 1 — Typical Results and Potential-Flow-Interaction Effects

Korakianitis

1988

Volume 1: Turbomachinery

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This paper is a contribution to the study of the generation of unsteady forces on turbine blades due to potential-flow interaction and viscous-wake interaction from upstream blade rows. A computer program is used to compute the unsteady forces on a rotor. The accuracy of the computer program is tested by comparing the results of a steady-flow calculation case and of an unsteady-flow calculation case with theory and experiment respectively. Results are shown for typical stator-to-rotor-pitch ratios and stator outlet-flow angles. These results show that the first spatial harmonic of the unsteady force may decrease for higher stator-to-rotor-pitch ratios. This trend is explained by considering the mechanisms by which the unsteady forces are generated. In this paper the mechanism by which the potential-flow interaction affects the flow field to generate these unsteady forces is shown to vary with the stator-to-rotor-pitch ratio and with the outlet flow angle of the stator.

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Section: The Computer Programmentioning

confidence: 99%

On the Prediction of Unsteady Forces on Gas-Turbine Blades: Part 1 — Typical Results and Potential-Flow-Interaction Effects

Korakianitis

1988

Volume 1: Turbomachinery

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“…The erratic behavior of the laminar solution with increasing Reynolds number is consistent with what has been observed by others. 33,34 It is believed to be a re ection of the increasingly turbulent nature of the ow, but it is probably in part a numerical artifact because the grid and time step are insu cient to resolve the turbulent eddies. The turbulent predictions at Re = 9 0 ; 000 exhibit an early drag crisis consistent with experiment for increased free stream turbulence.…”

Section: Flow Field Predictionmentioning

confidence: 99%

Computation of Vortex Shedding and Radiated Sound for a Circular Cylinder

Jared

Christopher

Kenneth

et al. 1997

4th International Symposium on Fluid-Structure Interactions, Aeroelasticity, Flow-Induced Vibration and Noise: Volume I

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The Lighthill acoustic analogy approach combined with Reynolds-averaged Navier Stokes is used to predict the sound generated by unsteady viscous flow past a circular cylinder assuming a correlation length of ten cylinder diameters. The two-dimensional unsteady flow field is computed using two Navier-Stokes codes at a low Mach number over a range of Reynolds numbers from 100 to 5 million. Both laminar flow as well as turbulent flow with a variety of eddy viscosity turbulence models are employed. Mean drag and Strouhal number are examined, and trends similar to experiments are observed. Computing the noise within the Reynolds number regime where transition to turbulence occurs near the separation point is problematic: laminar flow exhibits chaotic behavior and turbulent flow exhibits strong dependence on the turbulence model employed. Comparisons of far-field noise with experiment at a Reynolds number of 90,000, therefore, vary significantly, depending on the turbulence model. At a high Reynolds number outside this regime, three different turbulence models yield self-consistent results.

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“…The efficiency of the code is maximized utilizing the CFL condition on allowable time increment for generalized coordinates as reported by Shang (9): (13) external and internal flows involving unsteady phenomena (8,9,10). The computer code used in this program is a degenerate version of a three-dimensional code developed by Shang (8,9) for operation on a vector processor. This algorithm requires a combination of alternating forward and backward differences for the predictor and corrector sweeps.…”

Section: Turbulence Modelmentioning

confidence: 99%

“…1 Since the flow in a supersonic compressor rotor contains complex viscous-inviscid interaction including shock waves, boundary layers, flow separation and unsteady phenomena, a numerical solution of the Navier-Stokes equations is required to accurately simulate the flow behavior. Thus, the complete time-dependent compressible Navier-Stokes equations are solved using an adaptation of a computer code developed by Shang (8,9). Variations of this code have been applied successfUlTy for internal flows in ducts (10), thus it seems appropriate for the present application.…”

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Navier-Stokes Solutions of Unsteady Flow in a Compressor Rotor

Scott

Hankey

1986

Volume 1: Turbomachinery

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In order to achieve more accurate predictions of unsteady flow in a transonic compressor rotor an existing numerical approach has been modified by incorporating a turbulence model. The computations are performed by solving the complete time-dependent compressible Navier-Stokes equations using MacCormack’s explicit finite difference algorithm. These equations are solved for the flow through two adjacent rotor blades at a stream surface near the blade tip subjected to the wakes emitted from upstream stators. At this radial location the flow enters the blade passage at an absolute Mach number of 0.66. The high blade curvature at this radial location produces a large region of separated flow on the suction surface with laminar flow. To more accurately resolve the features of this flow separation the Baldwin-Lomax algebraic eddy-viscosity turbulence model is incorporated into the numerical procedure in regions, near the blade surface. The unsteady flow features are represented at the inflow boundary through the use of characteristic variables involving the upstream and downstream running Riemann invariants and the entropy variation expressed in terms of the total pressure profile. At the outflow boundary the concept of a “second throat” or choke point is implemented in conjunction with supersonic outflow conditions. The results are compared with numerical results obtained without the use of a turbulence model (laminar) for a single blade passage. Improved agreement with limited experimental data is also noted.

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Oscillatory compressible flow around a cylinder

Cited by 20 publications

References 15 publications

On the Prediction of Unsteady Forces on Gas-Turbine Blades: Part 1 — Typical Results and Potential-Flow-Interaction Effects

On the Prediction of Unsteady Forces on Gas-Turbine Blades: Part 1 — Typical Results and Potential-Flow-Interaction Effects

Computation of Vortex Shedding and Radiated Sound for a Circular Cylinder

Navier-Stokes Solutions of Unsteady Flow in a Compressor Rotor

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