Mesoscale numerical approach to predict macroscale fluid flow problems

We present a detailed analysis of the lattice Boltzmann method to simulate an incompressible fluid flow problem. Thorough derivation of macroscopic hydrodynamics equations from the continuous Boltzmann equation is performed. After showing how the formulation of the mesoscale particle dynamics fits in to the framework of lattice Boltzmann simulations, numerical results of isothermal, thermal and multiphase fluid flow are presented to highlight the applicability of the approach. The objective of the paper is to gain better understanding of this relatively new approach for applied engineering problems in fluid transport phenomena

The importance of design characteristics in walking from student's perspective: a case study in Universiti Kebangsaan Malaysia

Walking is a common form of physical activity, which has a lot of both social and recreational impacts. It is studied as a way of achieving sustainability. Many researchers recommend that walking can increase mental and physical health. Spectators of new urbanism recommend that the good design will encourage walking. There are several characteristics for designing walkable communities, which were frequently described in researches by many authors. In this paper, the four criteria noticed for making walkable university campus include connectivity, accessibility, safety/security and comfort. These criteria have been assessed by gathering survey in the Universiti Kebangsaan Malaysia to find out if these criteria can cause or affect walkability in university campus and it has been supported by previous studies. The result of the survey shows that these criteria are important from students’ perspective as high numbers of the students consider these characters as important for walking activity. The conclusion is to achieve walkable university campus as it will be necessary to evaluate present walking conditions, research walking behavior in different settings and consider these four criteria in designing campus for improving walking condition

Dynamic analysis of flexible mechanical systems using LATDYN

A 3-D, finite element based simulation tool for flexible multibody systems is presented. Hinge degrees-of-freedom is built into equations of motion to reduce geometric constraints. The approach avoids the difficulty in selecting deformation modes for flexible components by using assumed mode method. The tool is applied to simulate a practical space structure deployment problem. Results of examples demonstrate the capability of the code and approach

Buneman instability in a magnetized current-carrying plasma with velocity shear

Buneman instability is often driven in magnetic reconnection. Understanding how velocity shear in the beams driving the Buneman instability affects the growth and saturation of waves is relevant to turbulence, heating, and diffusion in magnetic reconnection. Using a Mathieu-equation analysis for weak cosine velocity shear together with Vlasov simulations, the effects of shear on the kinetic Buneman instability are studied in a plasma consisting of strongly magnetized electrons and cold unmagnetized ions. In the linearly unstable phase, shear enhances the coupling between oblique waves and the sheared electron beam, resulting in a wider range of unstable eigenmodes with common lower growth rates. The wave couplings generate new features of the electric fields in space, which can persist into the nonlinear phase when electron holes form. Lower hybrid instabilities simultaneously occur at $k_{\shortparallel}/k_{\perp} \sim \sqrt{m_e/m_i}$ with a much lower growth rate, and are not affected by the velocity shear.Comment: Accepted by Physics of Plasm