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Showing 1 to 11 of 11 for “"unsteady separation"”.
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Evaluation of Turbulence Models for Unsteady Separation
Unsteady separation occurs in many physical flows due to time-varying adverse pressure gradients. This phenomenon may result in increased drag, decreased lift, and loss of efficiency or failure in flow devices. It is, therefore, important to predict and analyze unsteady separation in the design of …
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Unsteady separation control on wind turbine blades
Dynamic stall is one of the primary causes of unsteady loads on wind turbine blades. The process can be instigated by a multitude of factors, common in wind turbine operating environments, such as inflow turbulence, wind gusts and sustained yaw misalignment. The unsteady separation due to dynamic …
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An experimental study of unsteady separation in a two-dimensional flow
An experimental study of flow separation in an incompressible two-dimensional unsteady flow was undertaken with the aim of validating recently developed flow separation criteria, which are based on kinematic principles. Specifically, the so-called rotor-oscillator arrangement was utilized to …
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Unsteady separation point injection for pressure recovery improvement in high subsonic diffusers
Thesis (S.M. and E.A.A.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 2002.
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An experimental investigation of unsteady separation shock wave motion in a plume-induced, separated flowfield
An experimental investigation of the unsteady separation shock wave motion in plume-induced, boundary layer separated (PIBLS) flowfields has been conducted. The PIBLS flowfields were created in a blowdown-type wind tunnel designed specifically to produce PIBLS in a planar, two-stream, supersonic …
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Unsteady Flow and Force Development in the case of a Circular Cylinder
… larger aircraft that can be subjected to highly unsteady flow fields. Sensing the flow and using predictive modelling to mitigate the unsteady forces shows potential, yet requires a detailed knowledge of the aerodynamic principles at play. This work is a fundamental study into the underlying …
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Unsteady Skin-Friction Measurements on a Maneuvering Darpa2 Suboff Model
Steady and unsteady flow over a generic Suboff submarine model is studied. The skin-friction magnitudes are measured by using hot-film sensors each connected to a constant temperature anemometer. The local minima in the skin-friction magnitudes are used to obtain the separation locations. Steady …
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Study of flow past elliptic and circular cylinders using direct numerical simulation
… provide valuable insight into the phenomenon of unsteady separation and the structure of bluff body wakes. With this in mind, a single-domain, spectral collocation technique has been developed to simulate the full three-dimensional incompressible flow over elliptic cylinders. Results of two- and …
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Feedback control of separation in unsteady flows
… that Prandtl's zero-skin-friction criterion for separation is invalid for unsteady flows. Employing a Lagrangian approach, Haller (2004) derived an exact kinematic theory for unsteady separation in two-dimensional flows. This theory predicts separation at points where a weighted average of the …
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Unsteady boundary layers and separation
… characteristic properties of boundary layer and separation in unsteady flow, play a very important role in fluid and structural mechanics because of their drastic effect on control forces generated by aerodynamic surfaces and loads carried by aerodynamic structures. Prandtl's criterion for …
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Influence of aspect ratio on dynamic stall of a finite wing
The influence of aspect ratio, AR, on the unsteady aerodynamics of pitching wings was examined by comparing experimental performance, flow measurements, and computational results across a range of different AR wings. Performance measurements were acquired for three wings of AR = 3, 4, 5, and an …