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Showing 1 to 20 of 24 for “"wall model"”.
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Development and Validation of a Turbulence Wall Model for Compressible Flows with Heat Transfer
The computational cost to model high Reynolds number flows of engineering interest scales poorly with problem size and is excessively expensive. This fact motivates the development of turbulence wall models to lessen the computational burden. These models aim to provide accurate wall flux …
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A Stress-equivalent Spalart-Allmaras Wall Model with Local Boundary Conditions for RANS, DES, and LES
… to their effective use. In this thesis, a new wall model is developed based upon a modified version of the Spalart-Allmaras (SA) turbulence model that lessens the near-wall grid requirements. This is achieved by, below the log layer, making the eddy viscosity approach a constant, non-zero …
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Wall Modeled Large Eddy Simulation of Flow over a Wall Mounted Hump
… numerical simulation (DNS). However, LES of wall-bounded flows still requires a very high grid resolution in the inner wall layer making its widespread use difficult. Different attempts have been made in the past time to overcome this problem by modeling the near wall turbulence instead of …
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Large Eddy Simulations of high Reynolds number Complex Flows with Synthetic Inlet Turbulence
… number turbulent flows. The primary challenge in wall bounded flows is the need for very fine grids in the vicinity of walls, which makes LES impractical at high Reynolds numbers. An additional challenge is the accurate representation of inlet turbulent conditions for developing flows such that …
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IMPLEMENTATION AND PERFORMANCE OF WALL MODELS FOR LARGE EDDY SIMULATION OF NON-EQUILIBRIUM TURBULENT BOUNDARY LAYERS
Accurate prediction of high-Reynolds-number wall-bounded turbulent flows is essential for the understanding and flow control of many engineering applications such as aircraft, turbomachinery, and marine vehicles. Additionally, most practical flows exhibit nonequilibrium effects such as pressure …
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Wall-modeled Large-eddy Simulation Based on Building-block Flows
A unified subgrid-scale (SGS) and wall model—the building-block flow model (BFM) — for wall modeled large-eddy simulation (WMLES) is proposed by devising the flow as a collection of building blocks that enables the prediction of the eddy viscosity. The core assumption of the model is that simple …
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A GPU-Enabled Building Block Flow Model for Computational Fluid Dynamics
… with the GPU architecture. This has allowed wall-modeled large eddy simulation (WMLES), a higher fidelity simulation technique, to become practical for industry use. WMLES requires the use of both a sub-grid scale (SGS) model and a wall model in order to close the system of equations for …
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A Study of Immersed Boundary Method in a Ribbed Duct for the Internal Cooling of Turbine Blades
… resolve the boundary near the immersed surface, wall modeled LES (WMLES) is evaluated in the final part of this thesis. WMLES is used for simulating turbulent flow in a developing staggered ribbed U-bend duct. Three cases have been tested at a bulk Reynolds number of 10⁵: a stationary case; a …
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Statistical Calibration and Validation of a Homogeneous Ventilated Wall-Interference Correction Method for the National Transonic Facility
… for many types of mathematical and computational models in the aerospace industry. The increased emphasis on accuracy of data acquired from these facilities requires understanding of the uncertainty of not only the measurement data but also any correction applied to the data. One of the largest …
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INVESTIGATION OF MATERIALS AND ANALYSIS TECHNIQUES FOR PERFORMANCE ENHANCEMENT OF PERPENDICULAR MAGNETIC TUNNEL JUNCTIONS
… method to predict bit error rate based on domain wall model for the magnetic immunity of the bit array is proposed.
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AN EMPIRICAL STUDY OF FLOOD WAVE IMPACT PRESSURES TO DETERMINE THE EFFECTIVENESS OF NEW SEAWALL DESIGNS USING A DAM-BREAK APPROACH
… to reduce both their occurrence and severity. Seawalls of varying slopes with wave energy dissipaters to create various degrees of roughness on their surfaces have been proposed as a potential evolution in the design of coastal defences. This present study therefore aimed at investigating the …
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On the boundary conditions for dissipative particle dynamics (DPD)
… In this thesis, we aim at developing a new wall model in which there is virtually no density fluctuation near the wall boundary. Two test cases of Couette flow and lid driven cavity have been done to show that DPD can be used successfully to validate the results. In order to simulate flows …
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Development of Eagle3D Solver For Wall Modeled LES of Transonic Flows
<p>Wall modeled Large Eddy Simulation (LES) is an area of interest due to its ability to lower computational costs of LES simulation. Even with the application of wall models, LES still proves to have practicality issues when it comes to use in industry, due to the expertise, time, and …
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A numerical simulation model for a building with transparent insulation
… insulation material (TIM) in a solar collector wall has been proven to have a significant potential to reduce heating load in passive solar buildings. Transparent insulation transmits a high proportion of incident solar radiation onto a layer of thermal mass which subsequently slowly releases …
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Seismic retrofitting of the Ste-Justine Hospital in Montreal
… 65,000m², and none of the buildings have shear walls or bracing. The engineers have apparently been counting on the frame behavior of the continuous reinforced concrete structure to resist lateral forces. In their current conditions, the existing buildings do not meet the actual code …
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Wall Modeled Large-Eddy Simulations in Rotating Systems for Applications to Turbine Blade Internal Cooling
Large-Eddy Simulations (LES or wall-resolved LES, WRLES) has been used extensively in capturing the physics of anisotropic turbulent flows. However, near wall turbulent scales in the inner layer in wall bounded flows makes it unfeasible for large Reynolds numbers due to grid requirements. This …
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Wall-models for large eddy simulation based on a generic additive-filter formulation
… implications of merging two different turbulence modeling approaches are addressed by deriving the exact hybrid RANS/LES Navier-Stokes equations. These equations are derived by introducing an additive-filter, which linearly combines the RANS and LES operators with a blending function. The …
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Microparticle Influenced Electroosmotic Flow
… the particles were held stationary. A moving wall model was utilized to account for the particle velocity and the wall-induced electroosmotic flow. The particle-induced electroosmotic flow was also accounted for. A range of particle velocities were imposed in order to study the flow physics …
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The structure and mechanical behavior of bamboo and bamboo products
… of dry bamboo tissue are related. Cellular level models are developed and explored, with a focus on density. Density is a practical parameter: it corresponds to weight, and places bamboo in the broader context of cellular solids. Bamboo tissue is made up of parenchyma and vascular bundles, …
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Effects of a Flexible Foundation on the Response of a Timber Shear Wall
… foundations on the response of timber shear walls. Timber shear walls, which typically consist of structural-use panels, such as plywood or oriented strand board (OSB), attached to a frame made from dimension lumber with dowel-type fasteners such as nails, provide resistance to lateral …
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