J. Serrano-Arellano¹, J. M. Belman-Flores^2,*, I. Hernández-Pérez³, K. M. Aguilar-Castro³, E. V. Macías-Melo³, F. Elizalde-Blancas², J. M. Riesco-Ávila², F. J. García-Rodríguez⁴

CMES-Computer Modeling in Engineering & Sciences, Vol.123, No.2, pp. 571-602, 2020, DOI:10.32604/cmes.2020.08677

Abstract In the present study, an analysis of the heat and mass transfer in a ventilated cavity in a warm climate zone was carried out to analyze, among others, the temperatures and percentage of relative humidity (RH). The governing equations of the mathematical model were solved through the finite volume method. We used the k-ε turbulence mode to find the results of the variables of interest in seven climate records on a given day. The velocity of the inlet flow of the air-H₂O mixture was varied through the Reynolds number (Re) from 500 to 10000. The outdoor weather conditions considered were… More >

Wen Zhao, Dongxing Mao^*, Zaixiu Jiang

Sound & Vibration, Vol.53, No.1, pp. 37-46, 2019, DOI:10.32604/sv.2019.04368

Abstract In order to analyze the effect of the background flow on the sound prediction of fine-scale turbulence noise, the sound spectra from static and flow environments are compared. It turns out that, the two methods can obtain similar predictions not only at 90 deg to the jet axis but also at mid- and high frequencies in other directions. The discrepancies of predictions from the two environments show that the effect of the jet flow on the sound propagation is related to low frequencies in the downstream and upstream directions. It is noted that there is an obvious advantage of computational… More >

T. Watanabe, T.Gotoh

The International Conference on Computational & Experimental Engineering and Sciences, Vol.18, No.3, pp. 91-92, 2011, DOI:10.3970/icces.2011.018.091

Abstract The effects of polymer additives on decaying isotropic turbulence were numerically investigated using a hybrid approach. The approach consisted of a Brownian dynamics simulation with an enormous number of dumbbells and a turbulence DNS with large-scale parallel computations. A reduction of the energy dissipation rate and modification of the kinetic energy spectrum were observed when the reactions of the polymers were incorporated into the fluid motion. We found that results with few polymers and large replicas could approximate those with many polymers and smaller replicas as far as the large-scale statistics were concerned. More >

Rama Govindarajan¹, S. Ravichandran², Jason Picardo¹, Samriddhi Sankar Ray¹, S. Ganga Prasath¹, Vishal Vasan¹

The International Conference on Computational & Experimental Engineering and Sciences, Vol.22, No.4, pp. 194-194, 2019, DOI:10.32604/icces.2019.05206

Abstract A cloud is in turbulent motion. It contains water vapour, aerosol particles and liquid water droplets. Depending on local levels of supersaturation, condensation takes place onto the aerosol particles and tiny droplets are formed. Our studies are aimed at understanding how these droplets grow in a short time, thought to be of the order of ten minutes, from about a micron in size into raindrops, which are of the order of millimeters. An important part of the process is collisions between droplets, some of which results in coalescence. Caustics from a single vortex are shown to be important for enhancing… More >

M.M.R. Damasceno¹, J.M. Vedovoto¹, A. da Silveira-Neto¹

CMES-Computer Modeling in Engineering & Sciences, Vol.104, No.2, pp. 105-132, 2015, DOI:10.3970/cmes.2015.104.105

Abstract Turbulence is a phenomenon which presents peculiarities when it is experimented or simulated. This occurs due to its complexity and high sensibility to the inlet conditions of the turbulent flow fields, as well as the presence of a large range of time and length scales. A simplification for this situation is obtained with the use of approximations and turbulence models. In the present work, the Largeeddy Simulations methodology was applied, aiming the modeling of the previously mentioned complexity, which consists in using a filter to resolve the large scales while the remaining scales were determined by classical and dynamic Smagorinsky… More >

Nadjib Ghiti¹

CMES-Computer Modeling in Engineering & Sciences, Vol.99, No.3, pp. 195-208, 2014, DOI:10.3970/cmes.2014.099.195

Abstract This paper presents a large eddy simulation of three dimensional vertically impinging jet on a horizontal plate. The air impinging jet was simulated using the perturbed method based on a high vortex number in the jet inlet for different ranges of Reynolds number Re= 6000, 8000, 10000, 12000, 14000 and for the same distance between the jet and the impinging plate. The effect of the Reynolds number of the air jet impinging on a horizontal plate was studied; the study showed that the vorticity magnitude is increased with the increasing of the Reynolds number. The turbulent flow jet was decomposed… More >

A. Balabel^1,2,3, W. A. El-askary², S. Wilson²

CMES-Computer Modeling in Engineering & Sciences, Vol.95, No.6, pp. 483-499, 2013, DOI:10.3970/cmes.2013.095.483

Abstract In the present paper, the impingement of air jet on a heated flat plate subjected to a periodic oscillation is numerically and experimentally investigated. The motivation of the present research is the desire to enhance the heat transfer characteristics during the cooling process of a heated flat plate which can be found in many relevance industrial applications. In order to improve the heat transfer characteristics, a novel idea is utilized, where a periodical oscillation movement in form of sine wave produced from a Scotch yoke mechanism is applied to the heated flat plate. The obtained numerical results showed a good… More >

Ashraf Balabel¹

CMES-Computer Modeling in Engineering & Sciences, Vol.95, No.4, pp. 283-302, 2013, DOI:10.3970/cmes.2013.095.283

Abstract This paper presents the numerical results obtained from the numerical simulation of turbulent liquid jet atomization due to three distinctly different types of liquid jets/air orientations; namely, coflow jet, coaxial jet and the combined coflow-coaxial jet. The applied numerical method, developed by the present authors, is based on the solution of the Reynolds-Averaged Navier Stokes (RANS) equations for time-dependent, axisymmetric and incompressible two-phase flow in both phases separately and on regular and structured cell-centered collocated grids using the control volume approach. The transition from one phase to another is performed through a consistent balance of the interfacial dynamic and kinematic… More >

Ashraf Balabel¹,

CMES-Computer Modeling in Engineering & Sciences, Vol.89, No.4, pp. 283-301, 2012, DOI:10.3970/cmes.2012.089.283

Abstract This paper presents a novel numerical method for solving the twophase flow problems with moving interfaces in either laminar or turbulent flow regimes. The developed numerical method is based on the solution of the Reynolds- Averaged Navier Stokes equations in both phases separately with appropriate boundary conditions located at the interface separating the two fluids. The solution algorithm is performed on a regular and structured two-dimensional computational grid using the control volume approach. The complex shapes as well as the geometrical quantities of the interface are determined via the level set method. The numerical method is firstly validated against the… More >

L.Q. Moreira¹, F.P. Mariano², A. Silveira-Neto¹

CMES-Computer Modeling in Engineering & Sciences, Vol.75, No.2, pp. 113-140, 2011, DOI:10.3970/cmes.2011.075.113

Abstract Turbulence in fluid flow is one of the most challenging problems in classical physics. It is a very important research problem because of its numerous implications, such as industrial applications that involve processes using mixtures of components, heat transfer and lubrication and injection of fuel into the combustion chambers and propulsion systems of airplanes. Turbulence in flow presents characteristics that are fully nonlinear and that occur at high Reynolds numbers. Because of the nonlinear nature of turbulent flow, an increase in the Reynolds number implies an increase in the Kolmogorov wave numbers, and the flow spectrum becomes larger in both… More >