An investigation of transient three-dimensional buoyancy-driven flow and heat transfer in a closed horizontal annulus
Abstract Buoyancy-driven flow and heat transfer in a horizontal annulus bounded by two impermeable boundaries in the axial direction are numerically investigated in this work. A transient three-dimensional analysis of the end effects on heat transfer and the corresponding flow field is presented. The effects of the axial impermeable boundaries are shown to be characterized by retardation of the flow field through the viscous shearing force in regions near the end walls. The results show that the temperature distribution remains unchanged in the core region provided that the annulus length to outer radius ratio is larger than a critical value. Flow and temperature fields are found to be symmetrical with respect to the mid-axial plane of the annulus. A number of interesting features resulting from the sudden heating of the inner cylinder are presented. Finally, a thorough presentation of formation of flow and temperature fields as a result of the sudden heating of the inner cylinder is given.
Three-dimensional natural convection in an inclined cylindrical annulus
Abstract An analytical and experimental work is described on natural convection in an inclined cylindrical annulus enclosed in heated inner and cooled outer cylinders. Three-dimensional governing equations are transformed into the finite-difference equations and solved numerically using the successive over-relaxation (SOR) procedure. The three-dimensional structure of the fluid flow and temperature distributions as well as Nusselt numbers are obtained and the effect of inclination on them is examined. A flow visualization experiment using a tracer technique is conducted; photographs of streaklines confirm the three-dimensional flow structure obtained analytically.
Investigations of dielectric gratings using electrodynamic models based on volume integral equations
Eigenmodes of planar and cylindrical dielectric gratings (DGs) and electromagnetic wave scattering from multiplayer DGs are investigated. The DG characteristics are calculated using numerical-analytical solution of integral equations (IEs).