Significance of Nonsimilar Numerical Simulations in Forced Convection from Stretching Cylinder Subjected to External Magnetized Flow of Sisko Fluid

The practice of flowing effort is participating in various industries especially in nutrition productions all around the world. These fluids practices are utilized extensively in nutrition handling productions by making use of sticky liquids to produce valuable food manufactured goods in bulk. Nevertheless, such productions ought to guarantee that involved equipment such as pipelines are maintained clean as well as are cleared out for the efficient movement of fluids. The nonsimilar characteristics of involuntary convection from circular cylinder stretching in the axial direction subjected to an external flow of Sisko fluid characterized by the freely growing boundary layers (BL) are presented in this research. A circular cylinder is submerged in a stationary fluid. The axial stretching of the cylinder causes external fluid flow. The magnetic force of strength ″ B 0 ″ is enforced in the transverse direction. Because of the fluid's high viscosity, frictional heating due to viscous dissipation is quite significant. The flow is three dimensional but with no circumferential variations. The governing equations for axisymmetric flow that include the mass balance, x -momentum, and heat equation are modeled through conservation laws. The dimensionless system is developed by employing appropriate nonsimilar transformations. The numerical analyses are presented by adapting local nonsimilarity via finite-difference (FDM)-based MATLAB algorithm bvp4c. The characteristics of dimensionless numbers are determined by graphs that are plotted on momentum and heat equations. The nonsimilar simulations have been compared with the existing local similar solutions. Fluid velocity is increased as the material and curvature parameters are increased, resulting in improved heat transfer. The deviation in skin friction and local Nusselt number against the various dimensionless numbers is also analyzed.

Prograde and retrograde precession of a fluid-filled cylinder

We numerically study precession driven flows in a cylindrical container whose nutation angle varies between 60 and 90 degrees for prograde and retrograde precession. For prograde precession we observe sharp transitions between a laminar and a turbulent flow state with low and high geostrophic axisymmetric flow components related with a centrifugal instability, while for retrograde precession a rather smooth transition between a low state and a high state occurs. At the same time prograde and perpendicular precession shows an abrupt breakdown of the flow directly excited by the forcing mechanism, which is not the case for retrograde motion. We characterize the corresponding flow states in terms of the directly driven, non-axisymmetric Kelvin mode, the axisymmetric geostrophic mode, and an axisymmetric poloidal flow which is promising for precession-driven dynamo action. The latter issue is discussed with particular view on an optimal parameter choice for the DRESDYN dynamo project.

Convective transport of thermal and solutal energy in unsteady MHD Oldroyd-B nanofluid flow

In this work, an analysis is presented for the unsteady axisymmetric flow of Oldroyd-B nanofluid generated by an impermeable stretching cylinder with heat and mass transport under the influence of heat generation/absorption, thermal radiation and first-order chemical reaction. Additionally, thermal and solutal performances of nanofluid are studied using an interpretation of the well-known Buongiorno's model, which helps us to determine the attractive characteristics of Brownian motion and thermophoretic diffusion. Firstly, the governing unsteady boundary layer equation's (PDEs) are established and then converted into highly non-linear ordinary differential equations (ODEs) by using the suitable similarity transformations. For the governing non-linear ordinary differential equations, numerical integration in domain [0, ∞) is carried out using the BVP Midrich scheme in Maple software. For the velocity, temperature and concentration distributions, reliable results are prepared for different physical flow constraints. According to the results, for increasing values of Deborah numbers, the temperature and concentration distribution are higher in terms of relaxation time while these are decline in terms of retardation time. Moreover, thermal radiation and heat generation/absorption are increased the temperature distribution and corresponding boundary layer thickness. With previously stated numerical values, the acquired solutions have an excellent accuracy.

Physical model of fluid flows in spacecraft tank

The results of an experimental study of liquid fuel flows in the tanks of a spacecraft during its rotation are presented. The analysis of structure and character of flows development on time is carried out, variants of graphic dependences approximation are offered. Graphical diagrams are presented, according to which it is convenient to present a three-dimensional nonlinear picture of non-stationary axisymmetric flow in a spherical reservoir, as well as methods of influencing flows with the help of internal baffles. Estimation of the obtained experimental data probability testifies to the rather high quality of the measurement results and the constructed picture of the currents in the spherical tank with internal baffles.

Energy transport in axisymmetric flow on a rotating cylinder with heat source/sink and chemical reaction

In this article, a thermal analysis is conducted for the axisymmetric flow of viscous nanofluid induced by torsional motion of cylinder. Here the rotation of the cylinder is axially dependent. The impression of heat source/sink with chemical reaction is perceived on the thermal and concentration boundary layer, while the consequence of magnetic field is observed on the fluid flow. In addition, we utilized a two-phased model for nanofluids, namely Buongiorno's model to compute the outcomes of the Soret effect and Brownian diffusion. The non-dimensional ordinary differential equations (ODEs) are obtained by employing the similarity transformation into governing partial differential equations (PDEs). We employed a built-in function, viz. bvp5c, a finite difference method in Matlab®, to solve the BVPs. The acquired results showed that the axial component of the velocity field occurred as a wall jet phenomenon, which is due to an axial pressure gradient. The axial flow and energy of the system are lessened; however, the peak of the wall jet is amplified for higher values of Reynolds number, but the converse trend is observed in the case of the magnetic parameter. The influence of pertinent parameters is also scrutinized for the wall-shear stress, local Nusselt, and Sherwood number for a selected range of Reynolds number, i.e., [Formula: see text] Furthermore, the consequences of the magnetic field have been succinctly observed on the flow, temperature, and concentration profiles. It is concluded that the magnetic field creates a resisting force that causes a reduction in the velocity fields, while temperature profile is enhanced because of the thermal conductivity of nanofluid. The impression of heat source/sink elevated the energy of system, whereas chemical reaction reduced the concentration field.

ANALYSIS OF HYDRODYNAMICS IN THE SYNTHESIS OF CRYSTALS FROM WATER-SALT SOLUTIONS

In application to KDP crystal growth on a functioning crystallizer, the local features of solution hydrodynamics near the growing crystal surface, which may affect on the crystallographic conditions of crystal growth and the defect formation, are established by mathematical modeling. The design of a modernized crystallizer, which provides an axisymmetric flow around of a growing crystal by a water-salt solution, is considered.

Investigations into the opening of fractures during hydraulic testing using a hybrid-dimensional flow formulation

We applied a hybrid-dimensional flow model to pressure transients recorded during pumping experiments conducted at the Reiche Zeche underground research laboratory to study the opening behavior of fractures due to fluid injection. Two distinct types of pressure responses to flow-rate steps were identified that represent radial-symmetric and plane-axisymmetric flow regimes from a conventional pressure-diffusion perspective. We numerically modeled both using a radial-symmetric flow formulation for a fracture that comprises a non-linear constitutive relation for the contact mechanics governing reversible fracture surface interaction. The two types of pressure response can be modeled equally well. A sensitivity study revealed a positive correlation between fracture length and normal fracture stiffness that yield a match between field observations and numerical results. Decomposition of the acting normal stresses into stresses associated with the deformation state of the global fracture geometry and with the local contacts indicates that geometrically induced stresses contribute the more the lower the total effective normal stress and the shorter the fracture. Separating the contributions of the local contact mechanics and the overall fracture geometry to fracture normal stiffness indicates that the geometrical stiffness constitutes a lower bound for total stiffness; its relevance increases with decreasing fracture length. Our study demonstrates that non-linear hydro-mechanical coupling can lead to vastly different hydraulic responses and thus provides an alternative to conventional pressure-diffusion analysis that requires changes in flow regime to cover the full range of observations.