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Showing 1 to 20 of 24 for “"Transitional Flow"”.
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Laminar and Transitional Flow disturbances in Diseased and Stented Arteries
… compliance of arteries, and pulsatility of blood flow. Understanding of such hemodynamic regulation in relation to atherosclerosis is of significant clinical importance in the prediction and progression of heart disease as well as design of prosthetic devices such as stents. The current work will …
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CFD Modeling of Separation and Transitional Flow in Low Pressure Turbine Blades at Low Reynolds Numbers
… may be more likely to occur in the turbine flow passages. For accurate CFD predictions of the flow, correct modeling of laminar-turbulent boundary layer transition is essential to capture the details of the flow. To investigate possible improvements in model fidelity, both two-dimensional …
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Numerical Simulation of Flows past a Circular and a Square Cylinder at High Reynolds Number, and a Curved Plate in Transitional Flow
… models are applied for numerical simulation of flow past a circular and a square cylinder at high Reynolds number. Wray-Agarwal (WA) turbulence model is a recently developed one-equation turbulence model derived from k-w closure. Comparisons are made among computational results from WA model, …
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A Novel Multiblock Immersed Boundary Method Enabling High Order Large Eddy Simulation Of Pathological And Medical Device Hemodynamics
… disease progression, investigating blood flow patterns and evaluating medical device performance such as stent grafts and mechanical heart valves. Previous studies indicate the presence of highly disturbed, transitional and mildly turbulent flow in healthy and pathological arteries. …
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Verification, Validation and Application of Shear Stress Transport Transitional Model to a R/C Aircraft
… aircraft. The four-equation Menter-Langtry Transitional viscous model in ANSYS Fluent is applied to a number of 2D and 3D airfoils and wings operating within the transitional flow regime, to permit comparison to relevant experimental and numerical results for transition onset, extent, and …
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High Fidelity Studies in Closed-Loop Control of Unsteady Aerodynamics
… explore the success of a nonlinear, closed loop flow control strategy based on POD-ROM focusing on boundary-layer transitional flow in high-fidelity computational studies involving FDL3DI ILES code. Controlling the boundary-layer transition from laminar to turbulent allows the laminar …
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Quantification of Reynolds-averaged-Navier-Stokes Model Structural Hypothesis Uncertainty in Transitional Boundary Layer and Airfoil Flows
… uncertainty it induces on RANS predictions of transitional flows has been ignored so far due to the conceptual complexity involved in the associated uncertainty quantification. This type of uncertainty is called the model structural hypothesis uncertainty. In this thesis, a systematic …
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Numerical Study of Synthetic-Jet Actuation Effect on Airfoil Trailing Edge Noise
… accuracy and stability over the range of transitional flow regimes. In the adopted numerical procedure, the actuator is modeled without its resonator cavity through imposing a simple fluctuating-velocity boundary condition at the bottom orifice of the actuator. The orifice cavity with the …
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Turbulence models for the numerical prediction of transitional flows with RANSE
… ways to accurately compute high Reynolds number flows with Reynolds Averaged Navier-Stokes Equations (RANSE) solvers. In naval architecture, turbulence models are necessary to solve typical hydrodynamic problems both in model scale, where Re=O(106), and in full scale, typically Re=O(108), since …
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Numerical Simulation of the Transition Region in Hypersonic Flow
… combines a fully laminar and fully turbulent flow field through the indeterminacy to form the transitional flow field. GASP is a compressible Navier-Stokes code which has a practical lower working limit of M = .1. The majority of experimental data for transitional flow exists below this limit. …
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Effect of Flow-Acoustic Resonant Interactions on Aerodynamic Response of Transitional Airfoils
… study is conducted to examine the impact of flow-acoustic resonant interactions on the aerodynamic response of symmetric and cambered airfoils in the realistic transitional flow regimes with Rec=140,000 and M=0.0465 as well as the low Reynolds number flow regime with Rec=10,000 and M=0.2. The …
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The analysis of partially separated flow on sail systems using a sectional method
Yacht sail systems are subjected to low speed and transitional flow. Because of the<br/>supporting structure (mast and boom) of the sail system and the curvature of sail<br/>membrane, sail systems also have a partially separated flow.<br/><br/>In this work, it is introduced the sectional method as …
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Effect of Slot Span on Wing Performance
… Fluent models which include laminar-to-turbulent transitional flow effects. Convenient mathematical formulations are developed for use in aircraft conceptual design. First, a two-dimensional CFD comparison between different viscous models is performed in order to define the most accurate model at …
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Numerical Simulation of Plasma-Based Actuator Vortex Control of a Turbulent Cylinder Wake
… condition to model the actuator's effects on the flow. Validations of the moving wall for this simulation are set forth with the understanding that the moving wall can model the plasma actuator bulk flow effects at a distance downstream and not in a region near or on the plasma actuator. The …
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Quantifying Geomorphic Features: Relative Albedos, Skeletonization, and Multifractality
… site are more likely formed by dry granular flows than by groundwater. In a second investigation, I describe a new algorithm to derive the skeleton of a geomorphic polygon, such as the centerline for a river. This geomorphic study provides a persuasive illustration that geomorphology in …
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Incompressible flow over a three-dimensional cavity
… (CFD) method, the physics of incompressible flow passing over a three-dimensional cavity on a solid surface. This study has been divided into two parts: 1) incompressible laminar flow passing over a three-dimensional cavity; and 2) incompressible laminar-to-turbulent transition over a …
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Simulation of Isothermal Combustion in Gas Turbines
… challenges such as holding a flame in high-speed flow. The current research is aimed at determining whether such a combustion scheme is feasible using computational methods. The geometry, a simple 2-D cascade utilizes surface injection within the stator or rotor boundary layers (including the …
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High Resolution Simulation of Laminar and Transitional Flows in a Mixing Vessel
… describe and characterize the distinct flow regimes existing within a mixing vessel at various rotational speeds. This investigation is computational in nature and simulates the flow within a baffled tank containing a Rushton turbine of the standard configuration. For a Re based on …
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Parallel implementation and application of particle scale heat transfer in the Discrete Element Method
… In the fluidized bed, the highly energetic transitional flow and thermal field in the vicinity of the tube surface and the limits placed on the grid size by the volume-averaged nature of the governing equations result in gross under prediction of the heat transfer coefficient at the tube …
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Transition between Flow Regimes in Porous Media Using Magnetic Resonance Velocimetry: From Laminar to Turbulent
… to investigate the transition between different flow regimes in porous media. The complete transition spectrum of single-phase flow, from creeping flow to inertial, unsteady laminar, and turbulent flow regimes, was examined in sphere packings. Further understanding of the fundamental fluid …
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