Seyfolah Saedodin, M.S. Motaghedi Barforoush, Mohsen Torabi^*

Frontiers in Heat and Mass Transfer, Vol.2, No.4, pp. 1-4, 2011, DOI:10.5098/hmt.v2.4.4001

Abstract In this paper, a simplifying approach for calculating the radiant energy is achieved using the concept of net radiation heat transfer and provides an easy way for solving a variety of situations. This method has been applied to calculate the net radiation heat transfer between two long concentric semi-cylinders. Then this method used to calculate reduction heat transfer when radiation shields with temperature-dependent emissivity applied between these objects. Moreover, using this method the percentage reduction in heat transfer between two surfaces was calculated. The findings reveal that, one radiation shield with lower emissivity can reduce the net heat transfer even… More >

Niki Rezazadeh, Rezvan Abdi^*

Frontiers in Heat and Mass Transfer, Vol.7, pp. 1-6, 2016, DOI:10.5098/hmt.7.30

Abstract This study investigates the heat transfer in the mode of natural convection from a pair of hot cylinders to a cold square enclosure. Effects of boundary conditions of the enclosure on the rate of heat transfer from a pair of isothermal hot cylinders are investigated at a Rayleigh number of 10⁵ . The cylinders are arranged in a horizontal array at the middle height of enclosure. The commercial software, Fluent (V.6.3.26), is utilized to solve the problem using the Finite Volume Method. The streamlines as well as isothermal lines of the problem are reported. Moreover, the local Nusselt number on… More >

Zoubair Boulahia^* , Abderrahim Wakif, Rachid Sehaqui

Frontiers in Heat and Mass Transfer, Vol.8, pp. 1-10, 2017, DOI:10.5098/hmt.8.14

Abstract In the present work, natural convection heat transfer of Cu-water nanofluid inside a wavy wall enclosure is investigated numerically by using the finite volume discretization method. The study examines the effect of the nanoparticle volume fraction, the Rayleigh number, the wave amplitude, and the undulations number on the heat transfer rate. The results show that the heat transfer rate inside the wavy enclosure enhances by decreasing the wavy surface amplitude and increasing undulations number. It is also found that by increasing the volume fraction of nanoparticles and Rayleigh number, the heat transfer rate increases. More >

Hussein M. Jassim, Farooq H. Ali^* , Qusay R. Al-Amir, Hameed K. Hamzah, Salwan Obaid Waheed Khafaji

Frontiers in Heat and Mass Transfer, Vol.12, pp. 1-9, 2019, DOI:10.5098/hmt.12.22

Abstract This study is focused on the entropy generation of laminar natural convection inside a sinusoidal enclosure filled with air (Pr=0.71). The numerical investigation is performed for three shapes of inner cylinders (circle, square, and equilateral triangle) with the same area and different values of the Rayleigh number (10³-10⁶). Galerkin Finite Element Approach is utilized to solve the governing equations. The results showed that the entropy generations due to heat transfer, fluid friction and total entropy generation increase with increasing values of Rayleigh number, while the local Bejan number decreases. More >

Mahmud H. Ali^a,* , Rawand E. Jalal^a

Frontiers in Heat and Mass Transfer, Vol.15, pp. 1-14, 2020, DOI:10.5098/hmt.15.27

Abstract In this work, natural convection in an adiabatic enclosure with openings induced by two isothermal hot cylinders is approached numerically. The study covers five different configurations of the enclosure as the number and locations of the inlet and outlet ports are varied for Rayleigh number (Ra) between 10⁴ and 10⁶ . Additionally, the study also analyzes the effects of varying the horizontal distance (S) between the cylinders along with their vertical locations () for dimensionless values of 0.4 to 0.3 and -0.2 to 0.2, respectively, at a constant Ra of 10⁶ . The outcomes show that the locations of the… More >

Emad D. Aboud¹ , Qusay Rasheed Al-Amir², Hameed K. Hamzah², Ammar Abdulkadhim³, Mustafa M. Gabir³, Salwan Obaid Waheed Khafaji², Farooq H. Ali^2,*

Frontiers in Heat and Mass Transfer, Vol.17, pp. 1-17, 2021, DOI:10.5098/hmt.17.19

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=10³ -10⁶), undulation numbers (N=0,1 and 2), aspect ratios (AR=5, 2.5… More >

Zhiyun Wang^*, Ziqing Wang, Mo Yang

Frontiers in Heat and Mass Transfer, Vol.17, pp. 1-7, 2021, DOI:10.5098/hmt.17.10

Abstract This paper presents a two-dimensional fluid-structure interaction numerical simulation of fluid flow over two horizontal heat exchange cylinders affected by a flapping reed in a domain. The reed is a thin flexible sheet made of elastic material with one end fixed on the trailing edge of the upstream cylinder. The effects of the reed length and the cylinder spacing on the periodic oscillations of the reed, the flow field and the heat transfer of the downstream cylinder. The results show that the oscillation of the reed in this paper is a single-period oscillate model. Compared to the case of cylinder… More >

O. M. Oyewola^a,b,* , O. S. Ismail^b , M. O. Olasindeb , O. O. Ajide^b

Frontiers in Heat and Mass Transfer, Vol.18, pp. 1-8, 2022, DOI:10.5098/hmt.18.30

Abstract In this work, attempt is made to investigate the effect of cylindrical arrangement on the thermal and flow fields within the mixed convective regime for different values of Reynolds number within the study zone. Constructal design was used to design the flow geometric. Two-dimensional unsteady laminar flow equations with buoyancy force were solved numerically using finite element technique implemented on ANSYS FLUENT software. The study showed an optimised arrangement of 50% difference in coefficient of drag and 10% difference in Nusselt number within the geometrical arrangement variation. The effect of geometric arrangement is pronounced at low Ri than at high… More >

Yisu Xi¹, Binkai Shi², Wei Xu^1,3,*, Jing Ge⁴, Huaxin Zhu⁵, Dragoslav Sumarac^6,7

Structural Durability & Health Monitoring, Vol.16, No.2, pp. 163-177, 2022, DOI:10.32604/sdhm.2022.022082

Abstract With the aid of non-contact measurements of vibrating surfaces through laser scanning, operating deflection shapes (ODSs) with high spatial resolutions can be used to graphically characterize damage in plane structures. Although numerous damage identification approaches relying on laser-measured ODSs have been developed for plate-type structures, they cannot be directly applied to circular cylinders due to the gap between equations of motions of plates and circular cylinders. To fill this gap, a novel approach is proposed in this study for damage identification of circular cylinders. Damage-induced discontinuities of the derivatives of ODSs can be used to graphically manifest the occurrence of… More >

Yin Wang^1,*, Lingling Wang², Yong Ji¹, Zhicheng Xi¹, Wenwen Zhang¹

FDMP-Fluid Dynamics & Materials Processing, Vol.17, No.2, pp. 471-485, 2021, DOI:10.32604/fdmp.2021.014652

Abstract A three dimensional (3D) numerical wave flume is used to investigate carefully the ISWs (Internal solitary wave) forces acting on cylinders interacting with a stratified shear environment. Using the Large-Eddy Simulation (LES) approach and analyzing the distribution of shear stress and pressure along the surface of the cylinder, the differential pressure resistance and the viscous force are obtained. The method of multiple linear regression analysis is adopted and a comprehensive influence coefficient is determined accordingly to account for the dimensionless forces acting on the cylinder. Results show that the differential pressure resistance on a square cylinder is 1.5 times higher… More >