Olga Vlasova^*

FDMP-Fluid Dynamics & Materials Processing, Vol.20, No.9, pp. 2127-2137, 2024, DOI:10.32604/fdmp.2024.051202 - 23 August 2024

Abstract The dynamics of rotating hydrodynamic systems containing phase inclusions are interesting due to the related widespread occurrence in nature and technology. The influence of external force fields on rotating systems can be used to control the dynamics of inclusions of various types. Controlling inclusions is of current interest for space technologies. In low gravity, even a slight vibration effect can lead to the appearance of a force acting on phase inclusions near a solid boundary. When vibrations are applied to multiphase hydrodynamic systems, the oscillating body intensively interacts with the fluid and introduces changes in… 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 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 - 25 April 2022

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 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),… 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… 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 - 02 April 2021

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 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… 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 >

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 >

Subhankar Sen¹, Sanjay Mittal^{2, *}

CMES-Computer Modeling in Engineering & Sciences, Vol.113, No.1, pp. 35-55, 2017, DOI:10.3970/cmes.2017.113.033

Abstract The evolution of far wake of stationary elliptic cylinders with angle of attack is investigated for the unsteady flow at Re = 200 using a stabilized finite- element method. The Reynolds number, Re, is based on the major axis of cylinder and free-stream speed. Cylinder aspect ratios, AR considered are 0.2, 0.5 and 0.8 while the angle of attack, α varies from 0◦ to 90◦. With increasing α, the Karman or primary shedding frequency of each cylinder decreases monotonically while the primary wavelength and time-averaged as well as r.m.s. drag increase monoton- ically. The time-averaged… More >