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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 43 for “"Large Eddy Simulations (LES)"”.
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Entropy behavior for underresolved discontinuous Galerkin discretizations of the Navier-Stokes equations
… for aerodynamics. One application is for solving large eddy simulations (LES). The use of the discontinuous Galerkin (DG) discretization in particular has attractive properties for these simulations. The stabilization methods used for high-order DG for underresolved Navier Stokes perform some …
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Modeling of laminar-to-turbulent transition using a hybrid multi-scale simulation strategy
… to be computationally expensive, thus making large-eddy simulations (LES) a viable strategy. In LES, large scales of the flow field are computed, and the effects of small scales are modeled. In this study, the hybrid two-level large-eddy simulation strategy (TLS-LES) is being assessed for its …
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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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Design and development of a wind tunnel for the investigation of turbulent compressible mixing layers
… mixing layer flowfield by means such as large-eddy simulations (LES) and direct numerical simulations (DNS), and the maturation of high-resolution laser-based flow diagnostic techniques such as stereo particle image velocimetry (SPIV). The newly developed facility is characterized by its …
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Hydrogen Enrichment Effects on Thermoacoustics of Turbulent Partially Premixed Flames
… modes are excited are investigated using Large Eddy Simulations (LES) for a partially premixed swirl stabilised methane-air flame in a GTMC. Simulations are also performed for cases with methane-hydrogen blends revealing a similar bimodal instability, where the frequency of thermo acoustic …
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Coupled fluid structure simulations for application to grid-to-rod fretting
… mesh was constructed over the geometry. Large Eddy Simulations (LES) have been performed to accurately compute the turbulent forces acting on the spacers. Simulations were first performed for a rigid rod, as a reference decoupled solution. Fully coupled simulations were successively …
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A qualitative assessment and optimization of URANS modelling for unsteady cavitating flows
… is characterized by the formation of vapor bubbles when the pressure in a working fluid drops sharply below the vapor pressure. These bubbles, upon exiting the low-pressure region burst emanating tremendous amounts of energy. Unsteady cavitating flows have been influential in several aspects …
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Simulating Bluff-body Flameholders: On the Use of Proper Orthogonal Decomposition for Combustion Dynamics Validation
… the use of this technique by applying it to large eddy simulations of the bluff body stabilized premixed combustion experiment. Large-eddy simulations (LES) using both Fluent and OpenFOAM were conducted to reproduce experiments conducted in an experimental test rig which was built as part of …
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Lagrangian Parcel Volume method applied to icing surfaces to predict impact efficiency
… track the path and concentration of water particles; this will allow for a better representation of water impingement and ice accretion. This tracking can be accomplished by using either a Lagrangian computational method, which tracks particle paths with no diffusion, or an Eulerian computational …
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Simulations of turbulent swirl combustors
… combustors. The work presented here is based on Large Eddy Simulations (LES) coupled to an advanced combustion model: the Conditional Moment Closure (CMC). Numerical predictions have been systematically compared and validated with detailed experimental datasets. In order to analyze further the …
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Laser Diagnostics Applied to Lean Premixed Swirling Flames - Simultaneous Flow Field and Scalar Measurements
… for detailed studies of the turbulent flames. A large part of the work presented concerns experimental studies of lean turbulent premixed flames stabilized by a low-swirl burner. The unconfined flames that were studied were propagating in a divergent flow field and interacted with flow structures …
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Simulation of Flow in a Solid Fuel Ramjet Cavity
… a Solid Fueled Ramjet (SFRJ) is simulated using large eddy simulations (LES). A finite element method using a Discontinuous Galerkin bases has been implemented in the open-sourced multi-physics software SU2. Novel LES formulations of the fuel-gas boundary conditions and the heat release due to …
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Unsteady flamelet progress variable modeling of reacting diesel jets
… in Reynolds-averaged Navier-Stokes (RANS) simulations and large-eddy simulations (LES) to assess its accuracy. The RANS simulations predict that ignition occurs toward the leading tip of the jet, followed by ignition front propagation toward the stoichiometric surface, and flame propagation …
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Damping Parameter Study of a Perforated Plate with Bias Flow
… motors, afterburners (augmenters) and even large heaters/boilers is the dynamic instability also known as thermo-acoustic instability. Concerns with this ongoing problem have grown with the introduction of Lean Premixed Combustion (LPC) systems developed to address the environmental concerns …
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LES of Jets and Sprays Injected into Crossflow
… air stream prior to combustion. The numerical simulations regard three space dimensions and track also the flow dynamics by integrating the governing equations in time. The spatial and the temporal resolution are such that the large-scale flow structures are resolved. Such an approach is …
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Idealized particle-resolved large-eddy simulations to evaluate the impact of emissions spatial heterogeneity on CCN activity
Aerosol-cloud interactions remain a large source of uncertainty in climate models due to complex, nonlinear processes that alter aerosol properties and the inability to represent the full compositional complexity of aerosol populations within large-scale modeling frameworks. The spatial resolution …
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Broadband Noise Prediction of an Axial Compressor Operating at Low Reynolds Number
… 10^4$) regime presents new flow physics by the large regions of laminar flow that are present in the compressor. As such it is unclear how our conventional understanding of the noise sources in turbomachinery can be applied to this new regime. The research was conducted by designing and …
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Dynamics, stability and scaling of turbulent methane oxy-combustion
… flame stabilization physics at the large and small scales using experimental studies and numerical simulations. Experimental measurements are used to establish the stability characteristics of flame macrostructures in a swirl stabilized combustor. We show that the transition in the …
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Large Eddy Simulations of high Reynolds number Complex Flows with Synthetic Inlet Turbulence
The research was motivated by the desire to use Large Eddy Simulations (LES) to calculate liner heat transfer in industrial scale gas turbine combustors, which operate at high Reynolds numbers and high Swirl numbers. LES has several challenges which need to be surmounted for general application to …
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Hydrodynamic stability of a premixed flame subjected to transverse shear
… corrugated front with a cusp-like structure at a large scale. Once formed, the flame front always spikes towards the burned gas region and bows on the unburned gas region. The DL stability plays a crucial role in the hydrodynamic behaviors of a premixed flame and has many ramifications when …
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