Gravitational Effects in the Collision of Elasto-Viscoplastic Drops on a Vertical Plane

The collision of drops in a solid substrate is an interesting problem with several practical applications. When the drop is made of a complex fluid the problem presents numerical challenges due to the interaction of the mechanical properties and the free surface approach. In the present work, we solve the numerical problem of elasto-viscoplastic drops colliding in vertical plane. The free surface evolution is handled by a Marker-And-Cell method combined with a Front-Tracking interface representation. Special emphasis is given to the gravitational effects by means of exploring the Froude number. We were able to find a rich variety of outputs that can be classified as sticking, sliding, bouncing, detaching, and slithering.

A numerical model based on the curvilinear coordinate system for the MAC method simplified

In this paper we developed a numerical methodology to study some incompressible fluid flows without free surface, using the curvilinear coordinate system and whose edge geometry is constructed via parametrized spline. First, we discussed the representation of the Navier-Stokes and continuity equations on the curvilinear coordinate system, along with the auxiliary conditions. Then, we presented the numerical method – a simplified version of MAC (Marker and Cell) method – along with the discretization of the governing equations, which is carried out using the finite differences method and the implementation of the FOU (First Order Upwind) scheme. Finally, we applied the numerical methodology to the parallel plates problem, lid-driven cavity problem and atherosclerosis problem, and then we compare the results obtained with those presented in the literature.

Thermal Radiation on Mixed Convective Flow in a Porous Cavity: Numerical Simulation

In this paper, the influence of mixed convection in a porous square enclosure under the effect of radiation is numerically examined. The top and bottom walls are maintained at uniform temperature θc while some portion of the vertical walls is partially heated with temperature θh and rest of the vertical walls are thermally insulated, with θh > θc. The non-dimensional governing equations are solved by MAC (Marker and Cell) method. The effect of various parameters (thermal Grashof number, Darcy number, Prandtl number, Reynolds number) on flow patterns and heat transfer has been presented.

Effect of Participating Medium Radiation and Nano-Fluidic Behaviour of Atmospheric Aerosol on Natural Convection of Industrial Dusty Air

The current study is focused on thermal radiation interaction with the natural convection of atmospheric brown cloud (ABC). The current study puts emphasis on ultra fine carbon-black particle suspension of several nano meter range along with some pollutant gas mixture with atmospheric air. The numerical simulation of double diffusive thermo-gravitational convection of ABC is done with Hide and Mason laboratory model for atmosphere. The effect of flow circulation is simulated by setting different value of buoyancy ratios. The effect of participating media radiation has been investigated for various values of optical depth. The governing equations, describing circulation of ABC are solved using modified Marker and Cell method. Gradient dependent consistent hybrid upwind scheme of second order is used for discretization of the convective terms. Discrete ordinate method, with S8 approximation is used to solve radiative transport equation. Comprehensive studies on controlling parameters that affect the flow and heat transfer characteristics have been addressed. The results are provided in graphical and tabular form to delineate the flow behavior and heat transfer characteristics.

A HYBRID SCHEME FOR THREE-DIMENSIONAL INCOMPRESSIBLE TWO-PHASE FLOWS

We present a hybrid scheme for computations of three-dimensional incompressible two-phase flows. A Poisson-like pressure equation is deduced from the incompressible constraint, i.e., the divergence-free condition of the velocity field, via an extended marker and cell method, and the moment equations in the 3D incompressible Navier–Stokes equations are solved by our 3D semi-discrete Hermite central-upwind scheme. The interface between the two fluids is considered to be the 0.5 level set of a smooth function being a smeared out Heaviside function. Numerical results are offered to verify the desired efficiency and accuracy of our 3D hybrid scheme.

EFFECT OF ASYMMETRY AND ROUGHNESS OF STENOSIS ON NON-NEWTONIAN FLOW PAST AN ARTERIAL SEGMENT

Numerical investigations of non-Newtonian blood flow are carried out through an asymmetric arterial constriction (stenosis) obtained from casting of mildly stenosed artery [Back et al. [1984] Effect of mild atherosclerosis on flow resistance in a coronary artery casting by man, J. Biomech. Eng., Trans. ASME106, 48]. The Marker and Cell method, for governing equations of motion for the flow in primitive variables formulations is developed in a staggered grid to discretize the momentum equations representing the non-Newtonian viscous incompressible flow characterized by the generalized Power-law model in cylindrical coordinates system under axial symmetric conditions so that the problem effectively becomes two-dimensional. The modified pressure equation has been solved by Successive-Over-Relaxation method and the pressure–velocity correction formulae have been derived. Satisfactory level of convergence namely, the mass conservation of the order of 0.5 × 10-12 and consequently the steady-state criteria have been achieved. The separation points, reattachment points, pressure drop, and the wall shear stress distribution resulting from the present simulation agree well with the available numerical and experimental results. Secondary separation has also been predicted at higher Reynolds numbers. Further, in-depth study of the flow patterns reveals that shear-thickening model of generalized Power-law fluid experiences excess pressure drop more than that of shear-thinning model as in the case of flow past through cosine and smooth-shaped constrictions than irregular ones. The efficiency of the numerical code is illustrated by applying it to a test problem in order to validate the applicability of the technique as well as the simulation under consideration.