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Showing 1 to 20 of 80 for “"Reynolds stresses"”.
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Laser doppler anemometer measurements of Reynolds stresses in a fully developed pipe flow
A laser Doppler Anemometer (LDA) is used to make Reynolds stress measurements in a fully developed, turbulent pipe flow. Traverses are made to measure shear stress, normal stresses, and the correlation coefficient. To assess the accuracy of this system, these measurements are compared with results …
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Computation of Reynolds stresses in axisymmetric vortices and jets using a second order closure model
… second-order model [13] is used to close the Reynolds stress transport equations in cylindrical coordinates. A reduced set of equations are then solved for the decay of axisymmetric vortices and jets. A self-similar solution to the axisymmetric vortices is obtained numerically. The …
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Octant Analysis of the Reynolds Stresses in the Three Dimensional Turbulent Boundary Layer of a Prolate Spheroid
The Reynolds stresses in a three-dimensional turbulent boundary layer were examined using octant analysis. The representative flow was a pressure driven, three-dimensional turbulent boundary layer on the leeside (x/L=0.76-0.78, φ=105°-130°) of a 6:1 prolate spheroid at 10° angle of attack. The …
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The evaluation of turbulence models using tensor visualization techniques
… tensor, the tensor glyph, is used to present the Reynolds stresses found in turbulent flow. Various glyph types discussed in the literature are analyzed, and a glyph suitable for the Reynolds stress tensor is developed. This glyph is constructed so that the degree of anisotropy and the orientation …
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Use of computational fluid dynamics in the design of bubble column reactors
… flow models (laminar, k-e turbulence and the Reynolds stresses). mThis investigation raised many questions about how gas-liquid interactions are captured numerically. To answer some of these questions the analogy between thermal convection in a cavity and gas-liquid flow in bubble columns was …
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Physics-Informed, Data-Driven Framework for Model-Form Uncertainty Estimation and Reduction in RANS Simulations
… numerical simulation) of turbulent flows, the Reynolds-Averaged Navier-Stokes (RANS) equations based models are still the dominant tools for industrial applications. However, the predictive capability of RANS models is limited by potential inaccuracies driven by hypotheses in the Reynolds …
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Reynolds stress measurements downstream of a turbine cascade
… investigation was performed to measure Reynolds stresses in the turbulent flow downstream of a large-scale linear turbine cascade. A rotatable X-wire hot-wire probe that allows redundant data to be taken with solution for mean velocities and turbulence quantities by least-squares fitting …
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Error and uncertainty in estimates of Reynolds stress using ADCP in an energetic ocean state
… which are of similar magnitude to that of the Reynolds stresses.
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Turbulent interactions between stream flow and near-subsurface flow: a laboratory approach using particle image velocimetry and refractive index matching
… region and within the pore spaces at two flow Reynolds numbers. In additional experiments, a channel-spanning cylinder and a single spherical grain were mounted to the top of the bed to study the turbulent flow around obstacles adjacent to a highly permeable wall. Supplementary experiments …
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Implementation and Verification of a Synthetic Eddy Method (SEM) in the Eagle3d Compressible Flow Solver
… and capability of the SEM to reproduce given Reynolds stress profiles to start realistic turbulent behavior are verified using common academic cases. Eagle3D is a Computational Fluid Dynamics (CFD) solver using a novel combination of a Bounded Central Differencing (BCD) scheme with Weighted …
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Quantifying Near-Bank Turbulence Through a Storm Event
… flow events, quantifying the distribution of Reynolds stresses and turbulent kinetic energy (TKE) through a storm hydrograph, and identifying the relationship between hydraulic radius and turbulent stresses.;Three-dimensional velocity was measured using a Sontek 16-MHz ADV (Field) and …
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Near Wall Behavior of Vortical Flow around the Tip of an Axial Pump Rotor Blade
… vortex regions generate large production of the Reynolds stresses and turbulent kinetic energy. One of the most interesting features of the tip leakage flow is the bimodal velocity probability histograms of the v component due to the unsteady motion of the flow in the interaction region between …
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Structure of 2-D and 3-D Turbulent Boundary Layers with Sparsely Distributed Roughness Elements
… include mean velocities, turbulence quantities (Reynolds stresses and triple products), skin friction, surface pressure and oil flow visualizations in 2-D and 3-D rough-wall flows for Reynolds numbers, based on momentum thickness, greater than 7000. Very uniform circular cylindrical roughness …
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Experimental study of turbulent boundary layer flows over forward facing steps with different surface conditions.
… created using sandpaper 24-grits and 36-grits. Reynolds numbers based on step height and centerline mean velocities of 1200, 3600 and 4800 were employed. The results show that the mean reattachment length increases as Reynolds number increases over the smooth step. However, the mean reattachment …
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The Effects of Curvature on Turbulent Boundary Layers Over a 3D Bump Geometry: An Experimental Study Using BeVERLI Hill
… The study examines the mean velocity, Reynolds shear stresses, pressure gradient, turbulence intensity, and pressure coefficient variations in relation to the bump curvature. The results are consistent with prior studies on the destabilizing influence of concave curvature with …
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Experimental simulation of the wake of an axisymmetric body near a free surface
… were performed in a wind tunnel at a nominal Reynolds number of 6.0 x 10⁵. All turbulent flow parameters were measured at three streamwise stations. A Yawhead probe was used for the mean flow measurements, and a Constant Temperature Anemometer System with a 'x'-wire probe was used to obtain …
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An Experimental Study of Longitudinally Embedded Vortices in a Turbulent Boundary Layer via the Non-Invasive Comprehensive LDV Technique
… found to be most appropriate to correlate the Reynolds stresses and triple products, respectively. The higher inflow edge velocity and greater momentum thickness, creating a lower vortex generator to boundary layer height ratio, result in a more diffuse vortex as compared to previous work …
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An experimental investigation of the turbulent flow in a closed compound channel
… Measurements were made for a single channel Reynolds number. All mean velocity components were calculated and are reported. The mean velocity field results are in good agreement with results reported for similar geometries. The vector plots and the axial vorticity distribution reveal the …
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Direct Numerical Simulation of Flow Over Circular Cylinders for Large -Eddy Simulation Modeling
Flow over a circular cylinder at a Reynolds number of 1500 is studied using a three-dimensional direct numerical simulation (DNS). At this condition, the shear layer is unstable. However, previous direct numerical simulations of this flow have been limited to Reynolds numbers of 1000 or less, where …
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