Search for dissertations about: "weak boundary layer"

Showing result 1 - 5 of 17 swedish dissertations containing the words weak boundary layer.

2. 1. Boundary Layer Parametrization in Numerical Weather Prediction Models

   Author : Jacob Svensson; Gunilla Svensson; Michael Tjernström; Patrick Samuelsson; Stockholms universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; Boundary-Layer Meteorology; Numerical Weather Prediction; Turbulence parametrization; COAMPS; IFS; meteorologi; Meteorology;

   Abstract : Numerical weather prediction (NWP) and climate models have shown to have a challenge to correctly simulate stable boundary layers and diurnal cycles. This aim of this study is to evaluate, describe and give suggestions for improvements of the descriptions of stable boundary layers in operational NWP models. Two papers are included. READ MORE

4. 2. Adhesion to machined and laser ablated wood surfaces

   Author : Micael Stehr; KTH; []
   Keywords : LANTBRUKSVETENSKAPER; AGRICULTURAL SCIENCES; ablation; adhesion; checks; coating; cracks; excimer laser; gluing; IR laser; mechanical machining; mechanical weak boundary layer; microscopy; notched specimens; pine; planing; sample preparation; sawing; scanning electronmicroscopy; spruce; tip-cracks; UV laser; weak boundary layer; wood;

   Abstract : This thesis is a contribution to the R&D-program ValueActivation at KTH,Division of Wood Technology and Processingand containsfive papers related to the evaluation and development ofmachining techniques (mechanical and irradiation treatments)whereby weak boundaries at the wood surfaces in the form of(mechanical) weak boundary layers and (micro) cracks due tomechanical treatment can be avoided.The first paper describes the development of a method–using a UV laser–to study the mechanically weakenedboundaries. READ MORE

5. 3. Weak Boundary and Interface Procedures for Wave and Flow Problems

   Author : Qaisar Abbas; Jan Nordström; Peter Eliasson; Uppsala universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; weak boundary conditions; multiple penalty; finite difference methods; summation-by-parts; high order scheme; hybrid methods; MUSCL scheme; shocks; stability; energy estimate; steady-state; non-reflecting; Beräkningsvetenskap med inriktning mot numerisk analys; Scientific Computing with specialization in Numerical Analysis;

   Abstract : In this thesis, we have analyzed the accuracy and stability aspects of weak boundary and interface conditions (WBCs) for high order finite difference methods on Summations-By-Parts (SBP) form. The numerical technique has been applied to wave propagation and flow problems. READ MORE

6. 4. Integration of graphene into MEMS and NEMS for sensing applications

   Author : Xuge Fan; Frank Niklaus; Peter Steeneken; KTH; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Micro-electromechanical systems MEMS ; Nano-electromechanical systems NEMS ; heterogeneous 3D integration; Graphene; single-layer graphene; double-layer graphene; bilayer graphene; chemical vapor deposition CVD ; suspended graphene beams; suspended graphene membranes; doubly clamped; fully clamped; silicon on insulator SOI ; vapor hydrofluoric acid VHF ; Young’s modulus; built-in stress; built-in tension; piezoresistivity; gauge factor; accelerometer; resonators; electromechanical sensing; advanced transducers; humidity; gas sensing; sensitivity; CO2 sensing; graphene grain boundary; line defects; optical microscopy; wire bonding; Electrical Engineering; Elektro- och systemteknik;

   Abstract : This thesis presents a novel approach to integrate chemical vapor deposition (CVD) graphene into silicon micro- and nanoelectromechanical systems (MEMS/NEMS) to fabricate different graphene based MEMS/NEMS structures and explore mechanical properties of graphene as well as their applications such as acceleration sensing, humidity sensing and CO2 sensing. The thesis also presents a novel method of characterization of CVD graphene grain boundary based defects. READ MORE

7. 5. Assessment and Some Improvements of Hybrid RANS-LES Methods

   Author : Sebastian Arvidson; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; LES; hybrid RANS-LES; zonal RANS-LES; embedded LES; PDH-LRN; log-layer mismatch; LES length scale; shock boundary-layer interaction;

   Abstract : Motivated by numerical analysis of a shock/boundary-layer interacting (SBLI) flow in a duct, where some typical existing hybrid RANS-LES methods become awkward to give accurate predictions of the shock-induced corner separation bubble, a new hybrid RANS-LES method, has been proposed. The model is based on a low-Reynolds-number (LRN) $k-\omega$ RANS model, which is one of the few models that are capable of giving reasonable predictions for the SBLI flow in RANS computations. READ MORE