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Showing 1 to 20 of 26 for “"Separated Flows"”.
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Separated Flows Over Non-slender Delta Wings
… dynamic-stall process during a streamwise gust. Separated flow near the wing apex is shown to reattach during the gust, resulting in lift enhancement. Strong favourable pressure gradients drive the flow to promote reattachment, even after the gust has terminated. Combining the steady-state and …
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Data-driven models for turbulent separated flows
L'abstract è presente nell'allegato / the abstract is in the attachment
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An oscillating hot wire for measurements in separated flows
… to allow mean-flow velocity measurements in separated flows. Disturbance velocities can also be measured in regions of interest. An oscillating-arm assembly provides a directional bias to the hot-wire probe, and a linear-step assembly steps the probe through the boundary layer. These …
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Efficient solutions of 2-D incompressible steady laminar separated flows
… two-dimensional incompressible laminar steady flows at moderate-to-high Reynolds numbers. The method uses an incremental multigrid method and an extrapolation procedure based on minimum residual concepts to accelerate the convergence rate of a robust block-line-Gauss-Seidel solver for the …
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An alternative to the Kutta condition for high frequency, separated flows
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 1992.
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Advances In Computational Fluid Dynamics: Turbulent Separated Flows And Transonic Potential Flows
Computational solutions are presented for flows ranging from incompressible viscous flows to inviscid transonic flows. The viscous flow problems are solved using the incompressible Navier-Stokes equations while the inviscid solutions are attained using the full potential equation. Results for the …
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An Experimental Spatio-Temporal Analysis of Separated Flows Over Bluff Bodies Using Quantitative Flow Visualization
… of the method for the study of turbulent flows are presented in detail. The developed system is employed in the documentation of time-varying turbulent flow fields. Initially we study the spanwise variation of the near wake of a low-aspect ratio, surface-mounted, circular cylinder piercing …
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Analysis of the dynamic stability derivatives for high angle of attack aircraft
… conditions at high angles of attack lead to separated flows making the aerodynamic model more difficult to obtain. In this research wind tunnel experiments are performed on an F-5 air-craft model at high angles of attack, with small oscillations about the body oriented roll axis. In addition …
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Development and Application of Particle Image Velocimetry in High-Speed Separated Flow: Two-Dimensional Base Cavities
… velocity data over a planar region in high-speed separated flows for the quantitative analysis of turbulent and unsteady flow structures. This PIV system is the first of its type to incorporate sub-micron seed particles and birefringent image shifting for the resolution of flow velocity in …
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Direct numerical simulations of separated and separated-reattaching flows on massively parallel processing computers
Direct numerical simulations of separated-reattaching and separated flows have been performed on massively parallel processing computers. Two basic geometrical configurations have been studied: the separated-reattaching flow past a normal flat plate with an attached downstream splitter plate and …
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Flow Control Over a Circular Arc Airfoil by Periodic Blowing
The flow over sharp-edged wings is almost always separated. The control of separated flows is possible and benefits can be achieved but only in a time average sense. A new design of an actuator was designed and tested which can achieve a wide range velocity of without frequency dependence, is free …
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Development of a One-Equation Eddy Viscosity Turbulence Model for Application to Complex Turbulent Flows
… is the accurate simulation of complex turbulent flows using the Reynolds-Averaged Navier-Stokes equations in conjunction with a turbulence model. The goal of this research has been to develop an eddy viscosity type turbulence model to increase the accuracy of flow simulations for mildly separated …
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Numerical simulation and control of a fluid structure interaction for a plate in a transverse flow
… vortex method is used due to its relevance for separated flows, which implies approximating the flat plate by a thin ellipse. The simulation for a fixed plate has been completed with a plate approximated by a 20:1 ellipse and placed in an inviscid flow. A comparison with an image method is also …
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Techniques for compressible flow calculations on multi-zone grids
… results of the Baldwin-Lomax turbulent model for separated flows, only the attached flowtield is considered in the analytic forebody calculation. Finally, as applications of this approach, the inviscid/viscous flowfields about several aerodynamic bodies are calculated including a generic …
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Turbulence Modelling for Complex Flows in Turbomachinery
… be a more reliable tool for modelling complex flows in turbomachinery. To achieve this goal, a three-dimensional (3D) flow phenomenon that embodies many key features of turbomachinery flows, that is, the corner separation flow often found in axial compressor stators, is selected as the research …
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Post-stall hysteresis and flow field unsteadiness on an NACA 0012 airfoil
… regular bluff-body shedding frequency across the separated region of the airfoil. The low-frequency oscillations were observed to be more dominant for the upstroke branch, while the bluff-body shedding process was more dominant in the downstroke branch. The flow field unsteadiness was observed to …
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Machine Learning for Coherent Structure Identification and Super Resolution in Turbulent flows
… non-time resolved PIV measurements of turbulent flows. The primary goal is to utilize bayesian inference to automate turbulent coherent structure identification in boundary layer flows. Automated identification was hitherto hindered by the lack of a priori information about the convecting …
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Development and Application of Hybrid Wray-Agarwal Turbulence Model and Large-Eddy Simulation
… often produce low accuracy results for many flows. In recent years, the Large Eddy Simulation (LES) approach has been developed which has shown promise of achieving higher accuracy, however it is computationally very intensive and therefore has remained limited to computing relatively simple …
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An adaptive high order Reynolds-averaged Navier-Stokes solver with transition prediction
… the equations that govern compressible turbulent flows. In particular, this thesis describes a novel methodology to adapt the boundary layer mesh to the solution "on the fly", based on a measure of the boundary layer thickness that drives the position of the nodes in the mesh, without changing its …
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The effect of gas on multi-stage mixed-flow centrifugal pumps
… the flow features in single and multiphase flows. Laser Doppler Velocimetry and high speed imaging in single phase flow showed a high turbulence level in the wake of the impeller blades, and recirculation cells at low flow rates. In gas-liquid conditions, we demonstrated that the bubble size …
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