Arvind Pattamatta^a,*, Ghanshyam Singh^b

Frontiers in Heat and Mass Transfer, Vol.3, No.2, pp. 1-11, 2012, DOI:10.5098/hmt.v3.2.3005

Abstract The present study deals with the assessment of different turbulence models for heated wall jet flow. The velocity field and thermal characteristics for isothermal and uniform heat flux surfaces in the presence of wall jet flow have been predicted using different turbulence models and the results are compared against the experimental data of Wygnanski et al. (1992), Schneider and Goldstein (1994), and AbdulNour et al. (2000). Thirteen different turbulence models are considered for validation, which include the Standard k-ε (SKE), Realizable k-ε (RKE), shear stress transport (SST), Sarkar & So (SSA), v ² -f, Reynolds stress Model (RSM), and Spalart… More >

Vasishta Bhargava Nukala^*, Chinmaya Prasad Padhy

Sound & Vibration, Vol.58, pp. 133-150, 2024, DOI:10.32604/sv.2024.047762

Abstract A significant aerodynamic noise from wind turbines arises when the rotating blades interact with turbulent flows. Though the trailing edge of the blade is an important source of noise at high frequencies, the present work deals with the influence of turbulence distortion on leading edge noise from wind turbine blades which becomes significant in low-frequency regions. Four quasi-empirical methods are studied to verify the accuracy of turbulent inflow noise predicted at low frequencies for a 2 MW horizontal axis wind turbine. Results have shown that all methods exhibited a downward linear trend in noise spectra for a given mean wind… More >

Naima Krarraz^1,*, Amina Sabeur¹, Khadidja Safer², Ahmed Ouadha¹

FDMP-Fluid Dynamics & Materials Processing, Vol.20, No.1, pp. 79-96, 2024, DOI:10.32604/fdmp.2023.026238

Abstract Any biogas produced by the anaerobic fermentation of organic materials has the advantage of being an environmentally friendly biofuel. Nevertheless, the relatively low calorific value of such gases makes their effective utilization in practical applications relatively difficult. The present study considers the addition of hydrogen as a potential solution to mitigate this issue. In particular, the properties of turbulent diffusion jet flames and the related pollutant emissions are investigated numerically for different operating pressures. The related numerical simulations are conducted by solving the RANS equations in the frame of the Reynolds Stress Model in combination with the flamelet approach. Radiation… More > Graphic Abstract

Loc Vu-Quoc^1,*, Alexander Humer²

CMES-Computer Modeling in Engineering & Sciences, Vol.137, No.2, pp. 1069-1343, 2023, DOI:10.32604/cmes.2023.028130

Abstract Three recent breakthroughs due to AI in arts and science serve as motivation: An award winning digital image, protein folding, fast matrix multiplication. Many recent developments in artificial neural networks, particularly deep learning (DL), applied and relevant to computational mechanics (solid, fluids, finite-element technology) are reviewed in detail. Both hybrid and pure machine learning (ML) methods are discussed. Hybrid methods combine traditional PDE discretizations with ML methods either (1) to help model complex nonlinear constitutive relations, (2) to nonlinearly reduce the model order for efficient simulation (turbulence), or (3) to accelerate the simulation by predicting certain components in the traditional… More >

Yuantao Liu¹, Yanzhe Li^1,*, Shanpeng Zhao^1,2, Youpeng Zhang¹, Taizhen Zhang³

FDMP-Fluid Dynamics & Materials Processing, Vol.19, No.10, pp. 2533-2547, 2023, DOI:10.32604/fdmp.2023.027471

Abstract Turbulence is expected to play a relevant role in the so-called conductor gallop phenomena, namely, the highamplitude, low-frequency oscillation of overhead power lines due to the formation of ice structures and the ensuing effect that wind can have on these. In this work, the galloping time history of a wire with distorted (fixed in time) shape due to the formation of ice is analyzed numerically in the frame of a fluid-solid coupling method for different wind speeds and levels of turbulence. The results show that the turbulence intensity has a moderate effect on the increase of the conductor’s aerodynamic lift… More > Graphic Abstract

Weiyu Zhang^a , Mo Yang^a,*, Yuwen Zhang^b

Frontiers in Heat and Mass Transfer, Vol.12, pp. 1-8, 2019, DOI:10.5098/hmt.12.18

Abstract The periodically fully-developed flow and heat transfer in channels with periodic semi-circular tube is studied numerically by the direct numerical simulation (DNS), the large eddy simulation (LES), and the Reynolds stress model (RSM). When the Reynolds number is between 3000 and 25000, the Nusselt number obtained by the RSM is closer to the experimental results than the results obtained from other turbulence models. The nonlinear characteristics of flow and heat transfer is revealed based on the results of numerical simulation. When Reynolds number is high, the geometric structure and boundary conditions of the channel are symmetric, but the flow field… More >

O. M. Oyewola^a,b,*, O. S. Ismail^b, J. O. Bosomo^b

Frontiers in Heat and Mass Transfer, Vol.17, pp. 1-5, 2021, DOI:10.5098/hmt.17.8

Abstract This paper investigates possible inherent modifications of the radiative heat source term due to the influence of turbulence in the thermal radiation field of a gas turbine combustor flame. Adapting a flame temperature of 2000[K], COMSOL Multiphysics software was utilized to numerically simulate the process, assuming a gray gas participating medium with absorption coefficient of 0.03[m^-1]. The analysis of the results for five (5) different radial cut sections of the simulated combustor chamber shows that turbulence-radiation interactions cause radiative heat losses from the flame, with the divergence of the radiative heat flux having a deviation factor of 3.48, and a… More >

Yu-Liang Zhang^a,* , Dong-Yang Wu^b, Hai-Bing Cai^c, Can-Fei Wang^c, Fei-Wu^c, Shao-Han Zheng^d

Frontiers in Heat and Mass Transfer, Vol.20, pp. 1-5, 2023, DOI:10.5098/hmt.20.11

Abstract In this paper, based on the Mixture model, the numerical computations of the internal flow field in a sewage pump are carried out. Through numerical simulation, the turbulence flow characteristics in the sewage pump are obtained. Results show that when the particle diameter is 0.10 mm, the solid-phase concentration on the volute surface is high, and the wear is more severe. When the particle diameters are 0.15 mm and 0.20 mm, the solid-phase concentration on the volute surface is significantly higher, especially when the over-current cross-section enlarges constantly. More >

Xin Sun¹, Chi Zhang³, Yan Jia^1,2,*, Shikang Sui¹, Chong Zuo¹, Xueqiang Liu¹

Energy Engineering, Vol.120, No.3, pp. 729-742, 2023, DOI:10.32604/ee.2022.023398

Abstract As a part of the new energy development trend, distributed power generation may fully utilize a variety of decentralized energy sources. Buildings close to the installation location, besides, may have a considerable impact on the wind turbines’ operation. Using a combined vertical axis wind turbine with an S-shaped lift outer blade and Φ-shaped drag inner blade, this paper investigates how a novel type of upstream wall interacts with the incident wind at various speeds, the influence region of the turbulent vortex, and performance variation. The results demonstrate that the building’s turbulence affects the wind’s horizontal and vertical direction, as well… More > Graphic Abstract

Dan Zhao^1,*, Qiong Wu¹, Minyao Gan², Ke Li¹, Wenhong Ma¹, Qun Wu¹, Liqiang Dong¹, Shaogang Liu¹

CMES-Computer Modeling in Engineering & Sciences, Vol.134, No.3, pp. 2041-2055, 2023, DOI:10.32604/cmes.2022.021026

Abstract To reduce the vibration and sound radiation of underwater cylindrical shells, a skin composed of micro floating raft arrays and a compliant wall is proposed in this paper. A vibroacoustic coupling model of a finite cylindrical shell covered with this skin for the case of turbulence excitation is established based on the shell theories of Donnell. The model is solved with the modal superposition method to investigate the effects of the structural parameters of micro floating raft elements on the performance of reducing vibration and sound radiation of the cylindrical shell of this skin. The results indicate that increasing the… More >