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Showing 1 to 20 of 58 for “"Unsteady Flows"”.
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Instabilities and unsteady flows in centrifugal pumps
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 1990.
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Feedback control of separation in unsteady flows
… 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 skin-friction vanishes. The …
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Numerical simulations of wings in unsteady flows
The unsteady vortex-lattice method is used to calculate the pressure coefficients on thick and thin airfoils in steady and unsteady flowfields. The parameters which affect the results, such as time step and aspect ratio, are studied. The effects of Reynolds number and thickness of a wing in steady …
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Extracting energy from unsteady flows through vortex control
… an adaptation of the classical linear theory for unsteady aerofoils. It combines the effects of nonuniform inflow and foil motion to predict the resulting thrust, lift, and moment. The numerical procedure allows for nonlinear interaction between the foil, performing large amplitude oscillations, …
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Numerical Simulation of Unsteady Flows of Physiological Relevance
Pulsatile flows in geometries of physiological relevance have been investigated. Atherosclerotic plaques are (initiated) near junctions and bifurcations in larger arteries. The flow in these regions is characterized by flow separation and unsteadiness, which indicates that local flow conditions …
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Extracting energy from unsteady flows through vortex control
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Ocean Engineering, 1994.
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Residual-Based Discretization Error Estimation for Unsteady Flows
… techniques to estimate discretization error for unsteady flows using the unsteady error transport equation (ETE) as well as defect correction. A framework to obtain exact truncation error and estimated truncation error is also presented. The technique and results for the steady-state cases are …
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A linearized Euler analysis of unsteady flows in turbomachinery
Thesis (Sc. D.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 1987.
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Investigation of a two-dimensional hydrofoil in steady and unsteady flows
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Ocean Engineering, 1991.
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On the Response of a Spherical Particle to Unsteady Flows at Finite Reynolds Numbers
The effect of turbulence on the motion of a freely settling particle is also investigated. In all cases considered, the inertial response time of the particle is the same as the Kolmogorov time scale of the freestream turbulence. Over the parameter range considered, turbulence is found to have a …
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Unsteady flows in cantilever compressor stator tip clearances and the effect of real tip geometry
… stator blades are performed to identify the unsteady and turbulent flow structure within compressor tip flows. The simulations were performed with clearances of 1.6 and 3.2 percent of chord. The results show that the flow both within the gap and at the exit on the suction side are highly …
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A methodology based on local resolution of turbulent structures for effective modeling of unsteady flows
… (CFD) is widely adopted to predict complex flows and to inform the design of advanced engineering systems. In particular, the industry has seen a continuous growth of CFD simulations of turbulent phenomena, which has been made possible by the tremendous reduction achieved in cost per …
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Transport in Lagrangian-unsteady flows : dipersion in diverging or converging ducts, and transport rate enhancement accompanying laminar chaos
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemical Engineering, 1997.
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Entrainment of Sediment by Unsteady Turbulent Flows
… that demonstrates the response of sediment to unsteady flows. The data that were gathered include temporal distributions of sediment concentration, shear stress, and velocity for two types of flow conditions: tests where the flow was increased from rest to a peak velocity and was then held …
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Design and calibration of a rapid-response thin-film heat flux gage
… was built, calibrated and tested for use in unsteady flows. The system was designed to maintain constant wall temperature boundary conditions. The measuring element is a thin-film heat flux gage made by sputter-coating gold on a substrate. A constant-temperature anemometer is used to maintain …
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The interaction forces in fluid-solid two-phase flows
… and solid phases is studied for both steady and unsteady flow situations. As a model, solid particles are assumed to be spherical and are distributed in regular arrays. For steady flows, a numerical method is used to calculate the interaction force for Reynolds number up to about 300. For …
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Unsteady Metric Based Grid Adaptation using Koopman Expansion
Unsteady flowfields are integral to high-speed applications, demanding precise modelling to characterize their unsteady features accurately. The simulation of unsteady supersonic and hypersonic flows is inherently computationally expensive, requiring a highly refined mesh to capture these unsteady …
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Unsteady boundary layers and separation
… 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 separation has been …
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