Heat transport mechanism via ion-slip and hall current in viscoplastic flow along a porous elastic sheet

Heat transfer phenomena occur in most of the natural as well as engineering or manufacturing production plants. Such significant industrial processes utilize various modes for the transportation of heat and energy. In this veneration, the existing research is an attempt to explore heat transmission in a viscoplastic fluid under thermal radiation in the presence of ion and Hall current. The properties of Hall and ion current have enormous uses, particularly when measured in the presence of heat transferal phenomena with suction and injection. The most relevant examples of such mechanisms are fridge spirals, magnetohydrodynamics accelerators, and control generators. Also, the field of biomechanics under the influence of these characteristics is widely used especially in the flowing of blood and magnetic resonance imaging, which helps in producing magnetic resonance images of the thorax, abdomen, brain, kidney, etc. Furthermore, directed medication transport inside the human body needs a tough and heavy magnetic field. Hence, these vital applications of Hall and ion current cannot be overlooked. Transport phenomena are examined past a porous elastic sheet. The prevailing physical model is adapted as a non-linear system of ordinary differential equations by means of proper similarity alterations. The graphical representation shows the physical implication of all related constraints on the velocity and temperature distribution of viscoplastic fluids. Momentum, as well as thermal boundary thickness, is significantly affected by Hall currents and ion slip parameters in the presence of suction/injection phenomena. The temperature of the fluid rises for Eckert number and radiation parameter and also the skin friction coefficient at the surface rises with the suction parameter. An excellent match of numerical results correctly up to three decimal places are obtained for the limiting case when compared to the already published literature.

Waves in elastic material

<div>Sea ice covers about 7% of the Earth's surface and 12% of the world's oceans. The presence of global warming and an increase in human activities in the polar region has resulted in significant interest in the behaviour of waves and ice interaction. In this study, the experimental investigation of waves-ice interaction is presented in the form of propagating waves in elastic materials. This investigation aims to study wave propagation, and energy transition as waves enter from open water to a water region covered with an elastic sheet. As the waves propagate in the elastic material, the waves immediately attenuate, suggesting a loss in energy. This loss in energy cannot be explained in the classical sense (breaking etc.) as the elastic sheet's existence prevents the breaking in waves of large amplitudes. The underlying mechanism as waves adapt to the elastic region is crucial for understanding the possibility of build-up in wave energy within the elastic sheet.</div><div> </div><div>For the experiments, a JONSWAP spectrum was used to generate wave fields. Ultrasonic probes were used to measure the surface elevation of the elastic layer and the open water free surface, and these two were compared. The attenuation rates are investigated as a function of distance. The spatio-temporal properties of the wave fields are investigated using 2D FFT to obtain the wavenumber-frequency spectrum. We find significant second-order nonlinear effects as the waves propagate with an elastic cover. Especially the occurrence of second-order difference interactions, sometimes called the group line, was found to be conspicuous in some of the wave fields.</div>

A note on the Stokes phenomenon in flow under an elastic sheet

The Stokes phenomenon is a class of asymptotic behaviour that was first discovered by Stokes in his study of the Airy function. It has since been shown that the Stokes phenomenon plays a significant role in the behaviour of surface waves on flows past submerged obstacles. A detailed review of recent research in this area is presented, which outlines the role that the Stokes phenomenon plays in a wide range of free surface flow geometries. The problem of inviscid, irrotational, incompressible flow past a submerged step under a thin elastic sheet is then considered. It is shown that the method for computing this wave behaviour is extremely similar to previous work on computing the behaviour of capillary waves. Exponential asymptotics are used to show that free-surface waves appear on the surface of the flow, caused by singular fluid behaviour in the neighbourhood of the base and top of the step. The amplitude of these waves is computed and compared to numerical simulations, showing excellent agreements between the asymptotic theory and computational solutions. This article is part of the theme issue ‘Stokes at 200 (part 2)’.

Chemically controlled shape-morphing of elastic sheets

A catalyst-coated 2D elastic sheet that generates controllable fluid flows can self-morph into multiple 3D structures in fluid-filled microchambers.