No abstract

The forced convective heat transfer and friction factor of nanofluids flow over a backward-facing step (BFS) in a channel with the base wall dissipating a uniform heat flux are experimentally investigated in this paper. Nanoparticles such as CuO and MgO dispersed in pure ethylene glycol (EG) with average diameters of 40 nm, and volume concentrations of 0, 1, 3, and 5% are considered as the working nanofluids. The results indicate that the heat transfer rate increases as the volume concentration of nanoparticles increased. The Nusselt number is enhanced up to 11% at 0.05 volume concentration compared to pure EG. The friction factor increases up to approximately 15% at Reynolds number (Re) of 5000 and volume concentrations of 0.01 and 0.03. The maximum value of the PEC in a BFS channel is 1.5 for the CuO-EG and 1.2 for the MgO-EG at a volume concentrations of 0.03 and Re = 20,000.

Various methods of flow control for enhanced aerodynamic performance have been developed and applied to enhance and control the behavior of aerodynamic components. The use of Coandă effect for the enhancement of circulation and lift has gained renewed interest, in particular with the progress of CFD. The present work addresses the influence, effectiveness, and configuration of Coandă-jet fitted aerodynamic surface for improving lift andL/D, specifically for S809 airfoil, with a view on its incorporation in the wind turbine. A simple two-dimensional CFD modeling usingk-ɛturbulence model is utilized to reveal the key elements that could exhibit the desired performance for a series of S809 airfoil configurations. Parametric study performed indicates that the use of Coandă-jet S809 airfoil can only be effective in certain range of trailing edge rounding-off radius, Coandă-jet thickness, and momentum jet size. The location of the Coandă-jet was found to be effective when it is placed close to the trailing edge. The results are compared with experimental data for benchmarking. Three-dimensional configurations are synthesized using certain acceptable assumptions. A trade-off study on the S809 Coandă configured airfoil is needed to judge the optimum configuration of Coandă-jet fitted Wind-Turbine design.

No abstract

A review of the aerodynamic modelling of insect flight is presented. This paper consists of two sections covering various aspects related to the development of flapping wing and research on the aerodynamic modelling of insect flight. First, we provide an overview of the nature of the flyers, including current issues and challenges related to the evolution of nature-inspired design. The second section discusses some of the techniques required to develop aerodynamic models, seeks to address issues and to identify appropriate aerodynamic modelling methods for the development of insect flight models. Experimental models of flapping wing insect are discussed, followed by numerical models. Finally, we highlight the development of prototypes in insect flight, on the design, sizing and classification of the flying insect prototypes.