Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 21 for “"detached eddy simulation"”.
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Detached Eddy Simulation of Turbulent Flow and Heat Transfer in Turbine Blade Internal Cooling Ducts
Detached Eddy Simulations (DES) is a hybrid URANS-LES technique that was proposed to obtain computationally feasible solutions of high Reynolds number flows undergoing massive separation with reliable accuracy. Since its inception, DES has been applied to a wide variety of flow fields, but mostly …
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Development and Application of Hybrid Wray-Agarwal Turbulence Model and Large-Eddy Simulation
… 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 flows from low to moderate …
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Quantification of Velocity at the Sparkplug in a Lab Scale Combustion Chamber
… optical combustion chamber. An Improved Delayed Detached Eddy Simulation (IDDES) study was done to understand the turbulence characteristics of the flow in the optical chamber. Spark anemometry was used to obtain a relationship between the spark plasma evolution and freestream velocity. Finally, …
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Computational Investigation of Perforated Plate Film Cooling Utilizing Conjugate Heat Transfer
… flow prediction accuracy. Finally, a Delayed-Detached Eddy Simulation using conjugate heat transfer is performed to demonstrate the improved velocity and temperature prediction accuracy over steady-state simulations, particularly in regions with large turbulent shear and boundary layers.</p>
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A Preliminary Study of Acoustic Prediction Technology Based on Detached Eddy Simulations for Supersonic Jets Impinging on Flat Plates
… a hybrid RANS/LES technique known as Delayed Detached Eddy Simulation (DDES). A transient solution is calculated using the pressure-based coupled solver formulation with the second-order bounded central-upwind spatial discretization and second-order implicit time marching scheme. Flow features …
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Comparison of RANS Modeling to Dual-Plane PIV Measurements of the Turbulent Tip Vortex Trailed from a Hovering Rotor
<p>Numerical simulations using the Reynolds-Averaged Navier-Stokes (RANS) equations were conducted to study the development and turbulent decay of the tip vortices in the wake produced by a hovering rotor. The computational results were compared to detailed, dual plane Particle Image Velocimetry …
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Numerical Simulations of Iced Airfoils and Wings
… Navier-Stokes approach. Comparisons between simulation results and experimental force data showed favorable comparison up to stall conditions. At and past stall condition, the aerodynamic forces were typically not predicted accurately for large upper-surface ice shapes. A lift-break …
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A Numerical and Experimental Evaluation of the Turbulent Heat Flux in a Heated Jet in Crossflow
… to film cooled turbine blades. Scale Resolving Simulations (SRS) are used to examine the flow numerically. A Detached Eddy Simulation (DES) methodology is examined but found to be ineffective at correctly capturing the physics of the flow. A Large Eddy Simulation (LES) numerical model is …
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Modeling of Rotor Wake Vortex Dynamics and Interactions in Non-Homogenous Vertiport Environments
… Reynolds-Averaged Navier-Stokes (URANS) and a detached eddy simulation using a hybrid Large Eddy Simulation (LES) via a KomegaSSTDDES model. This model serves to save computational time as well as allow for accurate results. The three cases run are isolated rotor, full ground effects and …
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An investigation into the application of LES and DES for prediction of flow and forces around an IACC yacht keel and marine bodies
… an approach into the applicability of Large Eddy Simulation (LES) and Detached Eddy Simulation (DES) for the prediction of forces and flow around marine bodies at high Reynolds number is presented. The main aim of the thesis was to investigate and assess the use of LES and DES based …
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The study on adaptive Cartesian grid methods for compressible flow and their applications
… Finally, based on an open source code, the detached eddy simulation (DES) is developed for massive separation flow, and it is used to perform the research on aerodynamic performance analysis over the wing with ice accretion.
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High-Fidelity Modeling of eVTOL Rotor Unsteady Aerodynamic and Aeroacoustic Response to Time-Harmonic Gust
… acoustic post-processor. First, a baseline rotor simulation is conducted under uniform inflow to validate the computational model against experimental data from the Virginia Tech full-scale acoustic measurements of the Joby Aviation 2017 prototype rotor. The comparison of thrust, torque, and sound …
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A Stress-equivalent Spalart-Allmaras Wall Model with Local Boundary Conditions for RANS, DES, and LES
… is achieved by, below the log layer, making the eddy viscosity approach a constant, non-zero value, and the velocity, which has a non-zero slip, varying approximately linearly with distance from the wall while maintaining the same total shear stress. The wall model introduces one parameter which …
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Aerodynamic and Acoustic Modeling for eVTOL Rotor Noise Prediction
… Navier-Stokes (2D-RANS) airfoil simulations with rotor loading predictions from the Comprehensive Hierarchical Aeromechanics Rotorcraft Model (CHARM), tonal noise calculations using the acoustic solver PSU-WOPWOP, and broadband noise predictions from the UCD-QuietFly framework. …
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Aerodynamics and aeroacoustics of flap side-edges
… performed to visualise the on-surface flow. A detached eddy simulation was performed on a geometry that consisted of a main element and a half span flap to understand the flowfield. From the experimental and computational investigation four sources of vorticity in the flowfield were identified, …
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Passive methods for suppressing acoustic resonance excitation in shallow rectangular cavities.
… on the shear layer thickness, a 2D numerical simulation using K-epsilon and Detached Eddy Simulation (DES) models has been carried out and compared to the experimental results. For both passive methods, the study included two cavities with different aspect ratios (L/D=1.0 and L/D=1.67, L: …
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Unsteady aerodynamics using high-order methods
… schemes are employed to this effect. The Detached Eddy Simulation (DES) method is considered for the turbulence modelling part. At the start of this project, the combination of high order Computational Aeroacoustics (CAA) numerical schemes, non-reflecting boundary conditions and DES …
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Propeller Noise Prediction of an Urban Air Mobility Vehicle in Urban Environment
… Hybrid turbulence-resolving approaches—Detached Eddy Simulation (DES) and Delayed Detached Eddy Simulation (DDES)—are coupled with the Ffowcs–Williams and Hawkings (FW–H) acoustic analogy to capture both unsteady flow dynamics and far-field sound radiation.</p> <p>The first part focuses …
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Active Drag Reduction of Ground Vehicles Using Air-Jet Wheel Deflectors
… tunnel experiments. The performance of large eddy simulation (LES) and detached eddy simulation (DES) was largely dependent on the time step and grid size to accurately resolve turbulent eddies. The standard k-e, realizable k-e, k-w, DES, and LES all trended towards a drag coefficient which …
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Numerical and experimental investigation of VG flow control for a low-boom inlet
… Reynolds-Averaged Navier-Stokes (RANS) simulations using three-dimensional, structured, chimera (overset) grids and the WIND-US code were conducted. Flow control cases included conventional and novel types of vortex generators at positions both upstream of the terminating normal shock …
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