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.
Results
Showing 1 to 20 of 271 for “"RANS"”.
-
Robust adaptive high-order RANS methods
… adaptive Reynolds-Averaged Navier-Stokes (RANS) method for the analysis of turbulent flows. Specifically, a discontinuous Galerkin (DG) discretization of the RANS equations and an output-based error estimation with an associated mesh adaptation algorithm is demonstrated. To improve the …
-
Quantification of structural uncertainties in RANS turbulence models
… in Reynolds averaged Navier-Stokes (RANS) turbulence models. This approach solves an inference problem by comparing the results of RANS calculations to direct numerical simulation. The adjoint method is used to efficiently solve an inverse problem to determine the RANS turbulent …
-
Turbulent partially premixed combustion: DNS analysis and RANS simulation
… generation and propulsion for all kinds of transport. Fuel-lean premixed combustion technology has been identified to be a promising approach, despite many difficulties involve, notably issues concerning flame stability and ignitability. A partially premixed system has been introduced to …
-
Assessment of RANS Turbulence Models for Strut-Wing Junctions
… in these studies have not been validated for transonic, high Reynolds number, junction flows. This study intends to assess turbulence models by comparing drag and surface streamlines obtained from experiment and CFD. The test model is a NACA 0012 fin at Mach number of 0.75 and a Reynolds number …
-
Assessment of RANS Turbulence Models for Hypersonic Flat Plates
… the performance of the Menter Shear Stress Transport (SST) and Spalart–Allmaras (SA) models on a group of hypersonic flat plate cases from a recent direct numerical simulation (DNS) database. Quantities of interest examined include velocity, temperature, turbulent kinetic energy, modeled …
-
Effects of Turbulence Modeling on RANS Simulations of Tip Vortices
… of this thesis is to quantify the effects of RANS turbulence modeling on the resolution of free shear vortical flows. The simulation of aerodynamic wing-tip vortices is used as a test bed. The primary configuration is flow over an isolated finite wing with aspect ratio, , and Reynolds number, …
-
Comparing Turbulent Dispersion Models for RANS Simulations of Particle-Laden Flows
… the field. Due to their low computational cost, RANS simulations remain the preferred method in the design phase of engineering solutions. The reduction in computational cost stems from the fact that RANS simulations neglect velocity fluctuations and solve for the time averaged velocity field. …
-
Computational aeroacoustic modelling using hybrid RANS/LES methods with modified acoustic analogies
This study considers a numerical approach to identifying noise mechanisms in tandem cylinders to understand aircraft landing gear as a primary contributor to airframe noise during approach and landing. Fluctuations in the flow properties induced by turbulence are computed as well as the …
-
Computational Simulations of a Non-body of Revolution Ellipsoidal Model Utilizing RANS
The ability of Reynolds Averaged Navier Stokes (RANS) models to predict the characteristics of a non-Body of Revolution (non-BOR) Ellipsoidal model is studied to establish the feasibility of utilizing RANS as a non-BOR concept design tool. Data unable to be obtained experimentally, such as …
-
A statistical jet-noise model based on the acoustic analogy and a RANS solution
… the Reynolds-averaged Navier-Stokes equations (RANS). It evaluates the jet-noise power spectral density (PSD) in the quiescent region outside the turbulent jet. It includes the following components:1. A propagation model based on the high- and low-frequency approximations of the Lilley analogy …
-
Geometry-Aware Modeling of Rough-Wall Turbulence Using Reynolds-Averaged Navier-Stokes (RANS) Frameworks
… role in drag prediction, energy efficiency, and transport processes in internal and external flows. Despite extensive research, the representation of roughness effects in Reynolds-Averaged Navier–Stokes (RANS) turbulence models remains fundamentally challenging. Classical approaches rely on …
-
Numerical Investigation using RANS Equations of Two-dimensional Turbulent Jets and Bubbly Mixing layers
… layers using Reynolds-Averaged Navier-Stokes (RANS) equations. The behavior of a turbulent jet confined in a channel depends on the Reynolds number and geometry of the channel which is given by the expansion ratio (channel width to jet thickness) and offset ratio (eccentricity of the jet …
-
Physics-Informed, Data-Driven Framework for Model-Form Uncertainty Estimation and Reduction in RANS Simulations
… flows, the Reynolds-Averaged Navier-Stokes (RANS) equations based models are still the dominant tools for industrial applications. However, the predictive capability of RANS models is limited by potential inaccuracies driven by hypotheses in the Reynolds stress closure. With the …
-
Evaluation of RANS-Based Turbulence Models for the Propagation of Stratified Fronts in Buoyancy-Driven Flow
… implemented Reynolds-averaged Navier-Stokes (RANS) approach to turbulence modeling has previously shown limitations in its ability to adequately predict buoyancy-driven f lows, including thermally stratified flow. Inaccuracies in these cases are often attributed to the Reynolds analogy, a …
-
A Stress-equivalent Spalart-Allmaras Wall Model with Local Boundary Conditions for RANS, DES, and LES
… and applied to ReynoldsAveraged Navier-Stokes (RANS), demonstrating accurate predictions of quantities of interest such as aerodynamic coefficients, surface pressure and temperature, skin friction, and heat transfer compared with standard RANS-SA, while requiring substantially less near-wall …
-
Aerodynamic and Aeroacoustic Analysis of Low Reynolds Number Propellers Using Higher-Order RANS Transition Turbulence Modeling
… layer phenomena like laminar separation, flow transition and reattachment. These effects are known to greatly alter the flow at and near the rotor wall, influencing its aerodynamic performance as well as the noise generated. Capturing these effects in our computational models is necessary to …
-
Comparison of RANS Modeling to Dual-Plane PIV Measurements of the Turbulent Tip Vortex Trailed from a Hovering Rotor
… 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 (PIV) measurements …
-
Aerodynamic comparison and validation of rans, K-ω, standard K-ɛ and URANS simulations of flat plate film-cooling
… work focuses on the numerical investigation of RANS and URANS analyses on a flat plate film cooling. The investigation aims to provide comparison between various turbulent models available for the Reynolds Average Navier Stokes (RANS) analyses and extended to unsteady Reynolds Average Navier …
Page 1 of 14