[PDF] Top 20 A vortex method for wall bounded turbulent flows

... new vortex laments into the ...of vortex laments and segments during the ...to vortex stretching, which increases the length of laments, the number of segments in the calculation rises at a somewhat ... See full document

... for turbulent channel flow using explicit ...for turbulent channel flow and to significantly reduce the numerical errors which are associated with high wavenumbers generated from the convective term of the ... See full document

... Tayor vortex flow to wavy-vortex flow is ...in wall-bounded shear flows is a three-step process involving rolls advecting stream- wise velocity, leading to streaks which become unstable ... See full document

... free-stream turbulence level to O(1). Close planes in the boundary layer enable instantaneous streamwise structures to link non-physically. The near-wall streaks extend over a distance of 1000 in wall ... See full document

... Two-dimensional vortex methods rely principally on a discretization of the continuous two-dimen- sional time-dependent vorticity eld into a large number of vortex \blobs" 5], whose position and strength ... See full document

... Incompressible vortex reconnections have an extensive bibliography (for a review of the work up to 1994, see Kida and Takaoka (1994) and Kerr and Hussain ...of vortex tubes were considered with an emphasis ... See full document

... dimensional vortex breakdown in a closed cylindrical container with a rotating end ...end wall is mainly due to the axial vortex breakdown which is characterized by four variables such as the height, ... See full document

... where s is a coordinate in the direction of the vorticity vector and s is a unit vector in that direction. Use of (3) removes the need to develop elaborate differencing formulas for the prolate spheroid geometry. Since ... See full document

... end wall, in which they found the formation of a concentrated vortex core along the center ...the vortex breakdown bubbles which appeared in steady-state flow in a closed cylindrical container with ... See full document

... turbulent flows. To date, an LES practitioner wishing to simulate a turbulent flow effectively assumes that the dynamics of large-scale, resolved eddies are dominated by the flow geometry along with ... See full document

... Turbulent flows are significantly affected by the presence of walls, where the viscosity-affected regions have large gradients in the solution variables and accurate presentation of the near- wall ... See full document

... In adverse pressure gradient flows, static pressure increases in the flow direction,.. in comparison with zero and favorable pressure gradient flows, where 5P/dx = 0 and.[r] ... See full document

... the vortex flow field as predicted by the standard k e model and R e /k e against experimental ...the wall, and also to the unsteadiness of the vortex breakdown region where the measurements plotted in ... See full document

... Instantaneous velocity fields in present study mark that some coherent structures are still present in the rough bed boundary layer flow. Visualization of instantanous velocity in vertical planes (Figure 5) shows that ... See full document

... So-called wall flows are usable in many technical applications as a simple and reliable device for exhausting of light materials as dust, smoke, hot air, ...such flows can make troubles by treatment ... See full document

... Secondly, we filtered the silhouette images in the time domain by selecting only pixels which appeared in the moth in video frames n–2, n and n+2, where n is the frame of interest. Because the wings move rapidly compared ... See full document

... In Chapter II observations of grain movement, at the bed, under the action of turbulent fluctuations are describ e d, and a brief literature survey on flow conditions[r] ... See full document

... The process of sound generation in a turbulent boundary layer by unsteady wall- shear stresses can be understood in terms of linear mode conversion at a solid boundary. Whereas small-amplitude perturbations ... See full document

... Nomenclature Rem Reynolds number for oscillatory flows, Um D / 11 3D Re~, Re c Critical Reynolds numbers for the onset of vortex shedding and threedimensionality Retc Critical Reynolds n[r] ... See full document

... Solid wall (an inviscid flow): velocity components pre- scribed so that the sum of velocity vectors equals to zero in its tangential ...Solid wall (a viscous flow): velocity components were prescribed so ... See full document