S. Srinivasan

S. Srinivasan, K. B. Nakshatrala

In this paper, we present a stabilized mixed formulation for unsteady Brinkman equation. The formulation is systematically derived based on the variational multiscale formalism and the method of horizontal lines. The derivation does not need the assumption that the fine-scale variables do not depend on the time, which is the case with the conventional derivation of multiscale stabilized formulations for transient mixed problems. An expression for the stabilization parameter is obtained in terms of a bubble function, and appropriate bubble functions for various finite elements are also presented. Under the proposed formulation, equal-order interpolation for the velocity and pressure (which is computationally the most convenient) is stable. Representative numerical results are presented to illustrate the performance of the proposed formulation. Spatial and temporal convergence studies are also performed, and the proposed formulation performed well.

S. Balasubramaniyan, B. Subathra, R. C. Hemesh et al.

Studying cyber-physical system (CPS) for a given network protocol and processor schedules is a challenging task. This investigation illustrates the role of TrueTime a MATLAB package for simulating CPS encapsulating information on processor schedules, and network protocols. Properties of CPS such as temporal behaviors, performance and stability can be studied using the TrueTime tool. Furthermore, these simulations can be used to benchmark design and propose design alternatives. The procedure to use the toolbox for simulations and instantiate various blocks to study CPS is illustrated in the paper. Finally, an illustrative example has been presented of CPS simulation with wireless network. Our example demonstrates that TrueTime is a useful tool for studying CPS performance, timing behavior, schedulability analysis, and studying suitable network protocols.