Sökning: "log books"

Visar resultat 21 - 25 av 420 avhandlingar innehållade orden log books.

1. 21. Methodologies for RANS-LES interfaces in turbulence-resolving simulations

   Författare :Sebastian Arvidson; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; zonal RANS-LES; aeronautics; RANS-LES interfaces; Hybrid RANS-LES; grey-area mitigation; log-layer mismatch; embedded LES; LES length scale; LES;

   Sammanfattning : Hybrid Reynolds-Average Navier-Stokes (RANS)-Large-Eddy Simulations (LES) techniques are now seen by the aeronautical industry as the most promising turbulence-resolving approaches for complex high-Reynolds-number turbulent flows with regard to cost and accuracy. However, connecting RANS and LES simulated flows is a challenging task and needs special attention in order to increase simulation robustness and accuracy. LÄS MER

3. 22. Optimal Design and Inference for Correlated Bernoulli Variables using a Simplified Cox Model

   Författare :Daniel Bruce; Hans Nyquist; Werner G. Müller; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Cox binary model; correlated binary data; log-odds ratio; D-optimality; E-optimality; power maximization; efficiency; Statistics; Statistik; statistik; Statistics;

   Sammanfattning : This thesis proposes a simplification of the model for dependent Bernoulli variables presented in Cox and Snell (1989). The simplified model, referred to as the simplified Cox model, is developed for identically distributed and dependent Bernoulli variables. LÄS MER

4. 23. Mimic: A Microscopic Simulation Model for Rural Road Traffic

   Författare :Stig O. Simonsson; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; computer model; time headway; log normal distribution; Chi-Square test; gap-acceptance; rural road network; car-following; traffic simulation model; alignment; sight distance; Kolmogorov-Smirnoff test; software system; statistics;

   Sammanfattning : The purpose of this dissertation is to outline the theoretical basis of a road traffic simulation model, named Mimic, that constitutes the key elements of a system for estimating road user effects and environmental impacts. The simulation model suggested is a microscopic road traffic simulation model and it is structured to be used for networks of rural roads. LÄS MER

5. 24. Extensions of the kernel method of test score equating

   Författare :Gabriel Wallin; Marie Wiberg; Jenny Häggström; Anton A. Béguin; Umeå universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Test equating; Nonequivalent groups; Standard error of equating; bandwidth selection; log-linear models; item response theory; Statistics; statistik;

   Sammanfattning : This thesis makes contributions within the area of test score equating and specifically kernel equating. The first paper of this thesis studies the estimation of the test score distributions needed in kernel equating. LÄS MER

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

   Författare :Sebastian Arvidson; Chalmers tekniska högskola; []
   Nyckelord :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;

   Sammanfattning : 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. LÄS MER