A. Subba Rao^a,* , V. Ramachandra Prasad^a , P. Rajendra^a , M. Sasikala^a , O. Anwar Beg^b

Frontiers in Heat and Mass Transfer, Vol.9, pp. 1-9, 2017, DOI:10.5098/hmt.9.2

Abstract In this article, we investigate the nonlinear steady state boundary layer flow and heat transfer of an incompressible Jeffery non-Newtonian fluid from a permeable horizontal isothermal cylinder. The transformed conservation equations are solved numerically subject to physically appropriate boundary conditions using a versatile, implicit, finite-difference technique. The numerical code is validated with previous studies. The influence of a number of emerging non-dimensional parameters, namely with Deborah number (De), surface suction parameter (S), Prandtl number (Pr), ratio of relaxation to retardation times (λ) and dimensionless tangential coordinate (ξ) on velocity and temperature evolution in the boundary… More >

Hayder A. Abdulbari ^1,2, Hassan D. Mahammed¹, Z. Hassan, Wafaa K. Mahmood³

FDMP-Fluid Dynamics & Materials Processing, Vol.12, No.2, pp. 86-101, 2016, DOI:10.3970/fdmp.2016.012.086

Abstract An experimental investigation was carried out to study the response of a turbulent pressure drop fluctuations to longitudinal groove riblets, involved two configurations being triangular and spaced triangular grooves with height 600, 800, 1000 μm and peak to peak spacing 1000 μm and 2000 μm respectively. Experiments were therefore performed at free stream velocity up to 0.44 m/sec, which were corresponding to Reynolds number (Re) 53000. The development of the obtained turbulent layer downstream of the grooves was then compared with the results from the corresponding smooth-wall case. To conclude, the effect of the spaced More >

Arafat A. Bhuiyan^a,c, M. Ruhul Amin^b, Jamal Naser^c, A. K. M. Sadrul Islam^a

Frontiers in Heat and Mass Transfer, Vol.6, pp. 1-11, 2015, DOI:10.5098/hmt.6.5

Abstract In this study, the effects of thermal and hydraulic characteristics of wavy fin and tube heat exchanger are investigated. Simulation has been carried out by a commercial computational fluid dynamics code, ANSYS CFX12.0. The main objective of this study is to investigate the flow characteristics in turbulent flow. Results are predicted for the turbulent flow regime (2100≤Re≤7000) and compared with author’s previous work for laminar (400 ≤Re≤1200) and transitional (1300≤Re≤2000) flow regime. Regarding turbulence, the k-ω model was used to predict the turbulent flow characteristics with 5% turbulence intensity. Predicted results were compared with the More >

M. Pastor¹, T. Blanc¹, V. Drempetic¹ , P. Dutto¹ , M. Martín Stickle¹, A.Yagüe¹

CMES-Computer Modeling in Engineering & Sciences, Vol.109-110, No.2, pp. 183-220, 2015, DOI:10.3970/cmes.2015.109.183

Abstract This paper presents a model (mathematical, rheological and numerical) for triggering and propagation of landslides presenting coupling between the solid skeleton and the pore fluid. The model consists of two sub models, a depth integrated model incorporating the propagation equations, and a 1D model describing pore pressure evolution. The depth integrated sub model is discretized using a set of SPH nodes, each one having an associated finite difference mesh for discretizing the pore pressure evolution. The model we propose differs from other depth integrated models with coupled pore pressures proposed in the past in the More >

Anand Shukla^a, Alok Chaube^b, Shailesh Guptac^†, Arvind Sirsath^c

Frontiers in Heat and Mass Transfer, Vol.5, pp. 1-8, 2014, DOI:10.5098/hmt.5.14

Abstract One of the traditional methods used to improve the efficiency of a gas turbine is to increases the inlet temperature; thereby increasing the power output and in turn, the efficiency. The internal cooling passages of blades are roughened by artificial roughness to improve the cooling performance. The present study investigates the convective heat transfer and friction factor (pressure drop) characteristics of a rib-roughened square duct. The test section of the duct is roughened on its top and bottom wall with V and ᴧ- shaped square ribs. In the study, the Reynolds number (Re) varied from 10,000… More >

L. Rodríguez-Tembleque¹, M.H. Aliabadi²

CMES-Computer Modeling in Engineering & Sciences, Vol.102, No.3, pp. 183-210, 2014, DOI:10.3970/cmes.2014.102.183

Abstract This work presents new contact constitutive laws for friction and wear modelling in fiber-reinforced plastics (FRP). These laws are incorporated to a numerical methodology which allows us to solve the contact problem taking into account the anisotropic tribological properties on the interfaces. This formulation uses the Boundary Element Method for computing the elastic influence coefficients. Furthermore, the formulation considers micromechanical models for FRP that also makes it possible to take into account the fiber orientation relative to the sliding direction, the fiber volume fraction, the aspect ratio of fibers, or the fiber arrangement. The proposed More >

F. Marín¹, F. Alhama¹, J.A. Moreno¹

CMC-Computers, Materials & Continua, Vol.43, No.1, pp. 1-20, 2014, DOI:10.3970/cmc.2014.043.001

Abstract The field of nanotribology in the last decades was established through the introduction of Atomic Force/Friction Force Microscopes. However, our theoretical understanding of the individual processes involved in friction force microscopy is limited. This work designs a reliable and efficient model for the stickslip phenomenon, following the rules of network simulation. The model is able to manage different types of potential between the tip and the sample surface, allowing different kinds of sample material and microscope tip properties to be simulated with only minor changes in the code. The most analysed tribological materials in technical More >

L. Rodríguez-Tembleque¹, A. Sáez¹, F.C. Buroni¹

CMES-Computer Modeling in Engineering & Sciences, Vol.96, No.2, pp. 131-158, 2013, DOI:10.3970/cmes.2013.096.131

Abstract A boundary element based formulation is applied to study numerically the tribological behavior of fiber-reinforced plastics (FRP) under different frictional contact conditions, taking into account the micromechanics of FRP. Micromechanical models presented consider continuous and short fiber reinforced plastics configurations. The Boundary Element Method (BEM) with an explicit approach for fundamental solutions evaluation is considered for computing the elastic influence coefficients. Signorini’s contact conditions and an orthotropic law of friction on the potential contact zone are enforced by contact operators over the augmented Lagrangian. The proposed methodology is applied to study carbon FRP under frictional More >

Dan Dumitriu¹, Ligia Munteanu¹, Cornel Brişan², Veturia Chiroiu¹, Rǎzvan-Vlad Vasiu², Octavian Melinte¹, Victor Vlǎdǎreanu¹

CMES-Computer Modeling in Engineering & Sciences, Vol.94, No.2, pp. 159-173, 2013, DOI:10.3970/cmes.2013.094.159

Abstract The continuum modeling of tire/road vibro-contact dynamics is developed in this paper by assuming continuum relationship between the contact force and the deformation. An important aspect of this model is that the damping depends on the indentation. In the continuum approach, no difference is made between impact and contact, and the friction law can be other than the Coulomb’s law. Since the road is rocky, a bristle model was chosen to take into account the effect of the road irregularities. The identification of the contact domain is performed by checking the minimum distance between bodies. More >

D. Cherrared¹, E. G. Filali¹

FDMP-Fluid Dynamics & Materials Processing, Vol.9, No.2, pp. 127-151, 2013, DOI:10.3970/fdmp.2013.009.127

Abstract Our study deals with the characterization of the flow and related heat transfer in a smooth, circular minichannel. A duct with a sudden (sharp-edged) contraction is also considered. Prediction of the pressure loss coefficient in this case is obtained via the commercial code CFX 5.7.1. This code is based on the finite volume method for the solution of the Navier-Stokes and offers several turbulences models (in this study we use the shear stress turbulence model - SST). The numerical results are compared with experimental results obtained for a configuration similar to those considered in the More >