Sökning: "Reynolds number"

Visar resultat 16 - 20 av 219 avhandlingar innehållade orden Reynolds number.

1. 16. Numerical Investigation of Turbulent Fluid Flow and Heat Transfer in Complex Ducts

   Författare :Masoud Rokni; Värmeöverföring; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; SED; WET; GGDH; RNG; RSM; EASM; Low-Reynolds; Non-linear k-e; Heat transfer; Turbulent; Complex ducts; Secondary flows; Temperature invariance; Energy research; Energiforskning;

   Sammanfattning : Th need for a reliable and reasonable accurate turbulence model without specific convergence problem for calculating duct flows in industrial applications has become more evident. In this study a general computational method has been developed for calculating turbulent quantities in any arbitrary three dimensional duct. LÄS MER

3. 17. Stress, Flow and Particle Transport in Rock Fractures

   Författare :Tomofumi Koyama; Lanru Jing; Marc Boulon; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Numerical simulation; laboratory experiments; rock fracture; coupled stress-flow-tracer test; shear displacement; fluid flow; particle transport; finite element method FEM ; particle tracking method; Navier-Stokes equation; Reynolds equation; streamline velocity dispersion.; Geoengineering; Geoteknik;

   Sammanfattning : The fluid flow and tracer transport in a single rock fracture during shear processes has been an important issue in rock mechanics and is investigated in this thesis using Finite Element Method (FEM) and streamline particle tracking method, considering evolutions of aperture and transmissivity with shear displacement histories under different normal stresses, based on laboratory tests. The distributions of fracture aperture and its evolution during shear were calculated from the initial aperture fields, based on the laser-scanned surface roughness features of replicas of rock fracture specimens, and shear dilations measured during the coupled shear-flow-tracer tests in laboratory performed using a newly developed testing apparatus in Nagasaki University, Nagasaki, Japan. LÄS MER

4. 18. Turbulence Modelling of Flows Related to Wall-Cooling Applications

   Författare :Stefan Jansson; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; low-Reynolds number models; second-order-moment closures; turbulent heat transfer; two-equation models; film-cooling; near-wall models; turbulence modelling;

   Sammanfattning : Engineering flows are generally characterised by complex strain field and turbulence structure arising from a combination of shear, curvature, separation and recirculation etc. Under such flow conditions, transport by turbulent velocity fluctuations can make a significant contribution to the transport of momentum, heat and mass. LÄS MER

5. 19. Homogenization of some problems in hydrodynamic lubrication involving rough boundaries

   Författare :John Fabricius; Guy Bayada; Luleå tekniska universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Mathematics; partial differential equations; calculus of variations; homogenization theory; tribology; hydrodynamic lubrication; thin film flows; Reynolds equation; surface roughness; Weyl decomposition; Matematik; Mathematics; Matematik;

   Sammanfattning : This thesis is devoted to the study of some homogenization problems with applications in lubrication theory. It consists of an introduction, five research papers (I–V) and a complementary appendix.Homogenization is a mathematical theory for studying differential equations with rapidly oscillating coefficients. LÄS MER

7. 20. Experimental and Numerical Investigations of Heat Transfer related to Gas Turbine Applications

   Författare :Safeer Hussain; Värmeöverföring; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; heat transfer; obstacle; vortex generator; pin fins; endwall; Nusselt number; thermal performance; film cooling effectiveness; contouring;

   Sammanfattning : Gas turbines are broadly used in aerospace and marine propulsion and power production etc.Investigation of heat transfer in gas turbines is a long-lasting and still an active subject ofresearch due to its tremendous importance. LÄS MER