Fully Conservative Higher Order Finite Difference Schemes for Incompressible Flow

Fluctuating lift on a circular cylinder: review and new measurements

Flow over a circular cylinder at Reynolds number 3900 is studied numerically using the technique of large eddy simulation. The computations are carried out with a high-order accurate numerical method based on B-splines and compared with previous upwind-biased and central finite-difference simulations and with the existing experimental data. In the very near wake, all three simulations are in agreement with each other. Farther downstream, the results of the B-spline computations are in better agreement with the hot-wire experiment of Ong and Wallace [Exp. Fluids 20, 441–453 (1996)] than those obtained in the finite-difference simulations. In particular, the power spectra of velocity fluctuations are in excellent agreement with the experimental data. The impact of numerical resolution on the shear layer transition is investigated.

Numerical studies of flow over a circular cylinder at ReD=3900

This work contributes to the study of flow over a circular cylinder at Reynolds number Re=3900. Although this classical flow is widely documented in the literature, especially for this precise Reynolds number that leads to a subcritical flow regime, there is no consensus about the turbulence statistics immediately just behind the obstacle. Here, the flow is investigated both numerically with large eddy simulation and experimentally with hot-wire anemometry and particle image velocimetry. The numerical simulation is performed using high-order schemes and a specific immersed boundary method. The present study focuses on turbulence statistics and power spectra in the near wake up to ten diameters. Statistical estimation is shown to need large integration times increasing the computational cost and leading to an uncertainty of about 10% for most flow characteristics considered in this study. The present numerical and experimental results are found to be in good agreement with previous large eddy simulation da...

Experimental and numerical studies of the flow over a circular cylinder at Reynolds number 3900

Hot-wire measurements were conducted in the very near wake (x/d⩽10) of a circular cylinder at a Reynolds number based on cylinder diameter, Re
d of 3900. Measurements of the streamwise velocity component with the use of single sensor hot-wire probes were found to be inaccurate for such flowfields where high flow angles are present. An X-array probe provided detailed streamwise and lateral velocity component statistics. Frequency spectra of these two velocity components are also presented. Measurements with a 4-sensor hot-wire probe confirmed that the very near wake region is dominantly two-dimensional, thus validating the accuracy of the present X-array data.

The velocity field of the turbulent very near wake of a circular cylinder

: The performance of the dynamic subgrid-scale eddy-viscosity model and the suitability of high-order accurate, upwind-biased numerical methods for large eddy simulations of complex flows are investigated in the case of the turbulent wake behind a circular cylinder at Reynolds number 3,900, based on freestream velocity and cylinder diameter The numerical method consists of high-order upwind-biased finite difference techniques applied to the compressible Navier-Stokes equations written in generalized coordinates Integration in time is done using a fully implicit, second-order accurate iterative technique The results of three fifth-order accurate simulations performed on identical grids with the least-squares version of the dynamic model, the fixed-coefficient Smagorinsky model, and with no subgrid-scale model are compared in the first 10 diameters of the wake The impact of three-dimensionality is also examined via two and three-dimensional calculations without a subgrid-scale model The effect of numerical dissipation is investigated by comparing two simulations using upwind-biased schemes, the first being fifth-order, and the second seventh-order accurate It is found that the near-wake is highly three-dimensional at this Reynolds number It contains pairs of counter-rotating streamwise vortices, the effect of which cannot be reproduced in two-dimensional calculations Three-dimensional computations are essential for predicting flow statistics of engineering interest (AN)

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Parviz Moin

Papers

Numerical experiments on the flow past A circular cylinder at sub-critical reynolds number