W. M. Faizal^1,*, C. Y. Khor¹, Muhammad Nooramin Che Yaakob¹, N. N. N. Ghazali², M. Z. Zainon², Norliza Binti Ibrahim³, Roziana Mohd Razi⁴

CMES-Computer Modeling in Engineering & Sciences, Vol.136, No.1, pp. 43-61, 2023, DOI:10.32604/cmes.2023.022716 - 05 January 2023

Abstract This paper aims to investigate and present the numerical investigation of airflow characteristics using Turbulent Kinetic Energy (TKE) to characterize the upper airway with obstructive sleep apnea (OSA) under inhale and exhale breathing conditions. The importance of TKE under both breathing conditions is that it show an accurate method in expressing the severity of flow in sleep disorder. Computational fluid dynamics simulate the upper airway’s airflow via steady-state Reynolds-averaged Navier-Stokes (RANS) with k–ω shear stress transport (SST) turbulence model. The three-dimensional (3D) airway model is created based on the CT scan images of an actual More > Graphic Abstract

Yan-Juan Zhao^a,*, Yu-Liang Zhang^b,† , Chen-Liang Zhang^b

Frontiers in Heat and Mass Transfer, Vol.17, pp. 1-7, 2021, DOI:10.5098/hmt.17.3

Abstract Vortex flowmeter adopts advanced micro processing technology, which has the advantages of strong function, wide flow range, simple operation and maintenance, convenient installation and use. It is widely used in petroleum, chemical industry, electric power, metallurgy, urban gas supply and other industries to measure various gas flows. In order to study the characteristics of the inner flow passage of the vortex flowmeter and reach the normal working standard of the vortex flowmeter, this paper uses CFX to calculate the turbulent kinetic energy, eddy viscosity and flow velocity of the inner flow passage of the vortex… More >

W. M. Faizal^1,2, N. N. N. Ghazali^2,*, C. Y. Khor¹, M. Z. Zainon², Irfan Anjum Badruddin^3,4,*, Sarfaraz Kamangar⁴, Norliza Binti Ibrahim⁵, Roziana Mohd Razi⁶

CMES-Computer Modeling in Engineering & Sciences, Vol.128, No.2, pp. 583-604, 2021, DOI:10.32604/cmes.2021.015549 - 22 July 2021

Abstract Background: Obstructive sleep apnea is a sleeping disorder that has troubled a sizeable population. There is an active area of research on obstructive sleep apnea that intends to better understand airflow behaviors and therefore treat patients more effectively. This paper aims to investigate the airflow characteristics of the upper airway in an obstructive sleep apnea (OSA) patient under light and heavy breathing conditions by using Turbulent Kinetic Energy (TKE), an accurate method in expressing the flow concentration mechanisms of sleeping disorders. It is important to visualize the concentration of flow in the upper airway in order… More >

Liang Ce, Yongchen Pan^*

FDMP-Fluid Dynamics & Materials Processing, Vol.16, No.6, pp. 1115-1128, 2020, DOI:10.32604/fdmp.2020.010829 - 17 December 2020

Abstract Two flow cases for scaled high speed train models with different length are numerically analyzed in the framework of the improved delayed detachededdy simulation model. Specific attention is paid to the shear flows and related mechanisms in the near turbulent wake created by these moving models. In particular, a comparative analysis is made on the distributions of turbulent kinetic energy (TKE) and turbulence production (TP) in planes perpendicular to the streamwise direction. The numerical results suggest that, in the wake region very close to the tail, significant TKE and TP can be ascribed to the More >

S. Torii¹

CMES-Computer Modeling in Engineering & Sciences, Vol.5, No.3, pp. 257-268, 2004, DOI:10.3970/cmes.2004.005.257

Abstract A numerical study is performed to investigate the thermal fluid-flow transport phenomena in the concentric annulus with a slightly heated rotating inner core moving in the flow direction and a stationary insulated outer cylinder. Emphasis is placed on the effects of the axial rotation and streamwise movement of inner core on the flow structure and heat transfer performance. A k-ε turbulence model is employed to determine the turbulent viscosity and the turbulent kinetic energy. The turbulent heat flux is expressed by Boussinesq approximation in which the eddy diffusivity for heat is determined using two-equation heat… More >