S M Deshpande
Articles written in Sadhana
Volume 1 Issue 4 December 1978 pp 441-458 Computer Simulation
The necessity for adopting a kinetic-theoretical approach to obtain aerodynamic characteristics in low density flow past space vehicles is highlighted in this paper; it is shown how long-standing difficulties in theoretically handling such flows can be circumvented by adopting a Monte Carlo technique. The principles underlying the technique are briefly described, and are first illustrated by applying the technique to the evaluation of the drag of cylinders and cones in collisionless flow.
The Markoff process underlying the Monte Carlo simulation of the full Boltzmann equation with collisions is then described in detail. Instead of the time-counter strategy of Bird, a theoretically sounder ‘Random Collision Number’ (RCN) strategy has been adopted in the present simulation. In this strategy the number of collisions in each time-step in the computation is a random number drawn from an appropriate distribution. Computer programs using this strategy have been developed for calculating aerodynamic characteristics like drag and heat transfer for a cone in the transition regime between free molecule and continuum flow. The results obtained from these programs show that both time-counter and RCN strategies require almost the same computer time.
Volume 38 Issue 1 February 2013 pp 1-1
Volume 39 Issue 1 February 2014 pp 149-164
The present paper deals with the development and application of a kinetic theory-based mesh-free method for unsteady flows. The method has the capability to compute on any arbitrary distribution of moving nodes. In general, computation of unsteady flow past multiple moving boundaries using conventional finite volume solvers are quite involved. They invariably require repeated grid generation or an efficient grid movement strategy. This approach becomes more difficult when there are many moving boundaries. In the present work, we propose a simple and an effective node movement strategy for the mesh-free solver. This can tackle the unsteady problems with moving boundaries in a much easier way. Using the present method we have computed unsteady flow in oscillating turbomachinery blades. A simple energy method has been used to predict flutter using the unsteady computations. The results compare well with the available experiments and other computations.