@Article{hmt.17.19,
AUTHOR = {Emad D. Aboud
, Qusay Rasheed Al-Amir, Hameed K. Hamzah, Ammar Abdulkadhim, Mustafa M. Gabir,
Salwan Obaid Waheed Khafaji, Farooq H. Ali},
TITLE = {NATURAL CONVECTON IN SINUSOIDAL–CORRUGTED ENCLOSURE  UTITIING SILVER/WATER NANOLUID WITH DIFFERENT SHAPES  OF CONCENTRIC INNER CYLINDERS},
JOURNAL = {Frontiers in Heat and Mass Transfer},
VOLUME = {17},
YEAR = {2021},
NUMBER = {1},
PAGES = {1--17},
URL = {http://www.techscience.com/fhmt/v17n1/52507},
ISSN = {2151-8629},
ABSTRACT = {The natural convection of nanofluid flow, which occurs between a sinusoidal-corrugated enclosure and a concentric inner cylinder has been numerically 
investigated. The two horizontal walls of this enclosure are considered adiabatic and two vertical corrugated walls are held at a constant value of the 
cold temperature while the inner concentric cylinder is heated isothermally. Different cylinder geometries (i.e, circular, square, rhombus, and triangular) 
located inside the enclosure are examined to find the best shape for optimum heat transfer. The physical and geometrical parameters influencing heat 
transfer are Rayleigh number (Ra=10<sup>3</sup> -10<sup>6</sup>), undulation numbers (N=0,1 and 2), aspect ratios (AR=5, 2.5 and 1.67) and two values for the volume 
fraction (φ=0 and 0.05). The numerical simulation was carried out using Comsol Multiphysics Software (5.3a). Galerkin approach along with the finite 
element method are used to solve equations of Navier-Stokes and energy with associated boundary conditions. In this study, validations of results 
between some available literatures and the present study found to be in an excellent agreement. Results indicate that the heat transfer and nanofluid 
flow characteristics in the sinusoidal-corrugated enclosure is significantly influenced by aspect ratio, undulation number, and Rayleigh number for all 
cylinder shapes. Thus, with the decrease in the aspect ratio, the intensity of streamlines becomes smaller, whereas, with rice in the Rayleigh number 
and undulation number, intensity increase is observed. Moreover, as the undulation number increases, the average value of the Nusselt number, 
including the hot surface of cylinders increases. At high Rayleigh numbers, the undulation number effect on the average value of the Nusselt number 
is more pronounced. Besides, the research showed that the circular cylinder shape inside the enclosure has the best heat transfer characteristics and 
flow than the others.},
DOI = {10.5098/hmt.17.19}
}