Buoyancy-driven heat transfer enhancement in a two-dimensional enclosure utilizing nanofluids

Heat transfer augmentation in a two-sided lid-driven differentially heated square cavity utilizing nanofluids

https://www.eis.hu.edu.jo/deanshipfiles/pub10311353.pdf

Numerical study of natural convection in partially heated rectangular enclosures filled with nanofluids

This review pertains to the body of work dealing with internal recirculating flows generated by the motion of one or more of the containing walls. These flows are not only technologically important, they are of great scientific interest because they display almost all fluid mechanical phenomena in the simplest of geometrical settings. Thus corner eddies, longitudinal vortices, nonuniqueness, transition, and turbulence all occur naturally and can be studied in the same closed geometry. This facilitates the comparison of results from experiment, analysis, and computation over the whole range of Reynolds numbers. Considerable progress has been made in recent years in the understanding of three-dimensional flows and in the study of turbulence. The use of direct numerical simulation appears very promising.

/pdf/fluid-mechanics-in-the-driven-cavity-25evptx577.pdf

Fluid mechanics in the driven cavity

Geometry: shape, size, aspect ratio and orientation Flow Type: forced, natural, laminar, turbulent, internal, external Boundary: isothermal (Tw = constant) or isoflux (q̇w = constant) Fluid Type: viscous oil, water, gases or liquid metals Properties: all properties determined at film temperature Tf = (Tw + T∞)/2 Note: ρ and ν ∝ 1/Patm ⇒ see Q12-40 density: ρ ((kg/m) specific heat: Cp (J/kg ·K) dynamic viscosity: μ, (N · s/m) kinematic viscosity: ν ≡ μ/ρ (m/s) thermal conductivity: k, (W/m ·K) thermal diffusivity: α, ≡ k/(ρ · Cp) (m/s) Prandtl number: Pr, ≡ ν/α (−−) volumetric compressibility: β, (1/K)

Convection Heat Transfer

Motion and heat transfer in the Blasius flow containing a pulsating component

A numerical study is made of the separated flow behind a flat plate. The plate is placed normal to the direction of the approach flow. The oncoming freestream velocity contains a pulsating part, U∞ = U 0 (1 + A 0 cos f p t). The temporal behavior of vortex shedding patterns is scrutinized over broad ranges of the two externally specified parameters, i.e., the pulsation amplitude (A 0 ≤ 0.6), and the dimensionless pulsation frequency, (f p ≤ 0.32). A version of the discrete vortex method is utilized. The variable-position nascent vortex technique is applied, and it proves to be adequate for pulsating approach flows. The numerical results clearly capture the existence of lock-on when f p exceeds a threshold value. The modulation of vorticity shedding is also detected when f p is reasonably low. The influence of A 0 on the flow characteristics is examined in detail. As A 0 increases to a moderate value (e.g., A 0 ≤ 0.6), an appreciable broadening is seen of the range of f p for which lock-on occurs. Based on the numerical results, three characteristic flow modes in the waves are identified. These findings are qualitatively consistent with the existing flow-visualization studies for a cylinder

Jae Min Hyun

Papers

Motion and heat transfer in the Blasius flow containing a pulsating component

Discrete Vortex Simulation of Pulsating Flow Behind a Normal Plate

Convection from a rectangular heated blockin pulsating channel flow

Augmentation of convective heat transfer by a torsionally-oscillating endwall disk

Transient sidewall shear layers of compressible fluid in a rapidly rotating circular-cylinder