Essays about: "Turbulent Boundary Layers"

Showing result 1 - 5 of 12 essays containing the words Turbulent Boundary Layers.

1. 1. On intermittency in the turbulent asymptotic suction boundary layer

   University essay from KTH/Skolan för teknikvetenskap (SCI)

   Author : Edoardo Foschi; [2023]
   Keywords : Turbulence; turbulent boundary layer; intermittency; numerical simulation; DNS; tripping; suction;

   Abstract : This thesis presents a series of direct numerical simulations (DNS) performed in order to understand the discrepancy in the literature regarding turbulent asymptotic suction boundary layers (TASBLs) at low Reynolds numbers. The hypothesis to be tested is that the main reason for higher turbulence intensities observed in experiments compared to DNS is that the latter exhibits intermittent patches of laminar flow, developing both temporally and spatially. READ MORE

3. 2. Turbulent Boundary Layers Modelling with Deep Operator Networks

   University essay from KTH/Skolan för teknikvetenskap (SCI)

   Author : Yu-Cheng Lu; [2023]
   Keywords : Turbulent Boundary Layers; Pressure Gradient; Composite Profiles; Deep Operator Networks; Sensitivity Analysis Nyckelord på svenska;

   Abstract : This thesis project aims to advance the modelling of pressure gradient turbulent boundary layers (PG TBLs) and offer new insights into TBLs modelling. Previous analytical studies have explored various mathematical models, but this research introduces an extended unstacked Deep Operator Networks (DeepONets) architecture with double outputs and five branch parameters. READ MORE

4. 3. Active flow control of the turbulent boundary layer over a NACA4412 wing profile for skin friction drag reduction

   University essay from KTH/Teknisk mekanik

   Author : Giacomo Semprini Cesari; [2023]
   Keywords : Active flow control; drag reduction; numerical simulations; turbulent boundary layer; wings;

   Abstract : In the context of building a framework for active flow control of turbulent boundary layers in wings, a set of large-eddy simulation (LES) are implemented in OpenFOAM. The flow around a NACA4412 wing profile is simulated at 5° angle of attack and Re_c = 400˙000. READ MORE

5. 4. Evaluation of a stochastic model of coherent turbulent structures for atmospheric particle deposition applications

   University essay from Uppsala universitet/Luft-, vatten- och landskapslära

   Author : Andreas Eriksson; [2022]
   Keywords : atmospheric dispersion; particle deposition; k-epsilon; RANS; lagrangian particle model; stochastic particle model; OpenFOAM; SIMPLE algorithm; ABL; atmospheric boundary layer; neutral boundary layer; coherent turbulent structures;

   Abstract : In this thesis, we have evaluated a stochastic Lagrangian model for computing particle deposition rates with prospects to use for atmospheric deposition applications.  The model is one-dimensional and models the particle dynamics in the boundary layers near walls and obstacles by simulating the coherent turbulent structures and Brownian motion governing the wall-normal transport. READ MORE

6. 5. Two-dimensional roughness and Tollmien-Schlichting waves: a study on transition

   University essay from KTH/Strömningsmekanik och Teknisk Akustik

   Author : Derek Micheletto; [2020]
   Keywords : ;

   Abstract : Two-dimensional (2D) roughnesses induce premature transition to turbulence in laminar boundary layers by amplifying the disturbances in the flow and promoting the development of non-linearities. The present thesis aims at furthering our understanding of this phenomenon's underlying mechanisms and elucidating the effects of the different geometrical parameters of the roughness' cross section. READ MORE