Computation of Aeroacoustics and Fluid Flow Problems Using a Novel Dispersion Relation Preserving Scheme

A new spectrally optimized physical dispersion relation preserving scheme has been introduced to solve computational acoustics and aeroacoustics problems, accurately. The derived fourth-order accurate scheme has significant spectral resolution and physical dispersion relation preserving (DRP) nature. The scheme displays neutral stability at high CFL numbers. The developed scheme has an ability to add numerical diffusion as and when required to attenuate spurious waves present in the computed solutions. These features make the proposed scheme suitable for solving computational aeroacoustic problems. The scheme has been validated by comparing solutions of model computational acoustic problems with the available analytical solutions. Scheme has also been tested to solve the incompressible flow field around a circular cylinder executing rotary oscillations. Ability of the scheme to perform direct simulation of the computational aeroacoustic problems has been shown by computing acoustic field triggered by a laminar flow past a stationary circular cylinder. Excellent match has been observed between the present computed results and the available results in the literature which justifies applicability of the present DRP scheme to solve complex flow and aeroacoustic problems.

A Novel Dedicated Route Protection Scheme for Survivability of Link Failure in Elastic Optical Networks

The spectrally efficient transportation of the high bit rate(s) data is achievable by the Elastic optical networks (EONs). However, in the EONs, owing to the failure occurrence even in an individual simple element, different service(s) maybe interrupted. Hence, it is imperative that the schemes for survivability be developed so that the issues due to the possible failure(s) can be overcome. In the current work, in view of survivability of the link failure(s) in the EONs, we propose the Spectrum Continuity and Contiguity Established DRP (SCC-E-DRP) algorithm which is a novel dedicated route protection (DRP) scheme that attempts to avoid the problem of trap topology during its exploration for a pair of link disjoint path. Further, to evaluate the link disjoint paths, we resort to the use of the SCC Established Shortest Route (SCC-E-SR) algorithm which is a modified Dijkstra’s algorithm based scheme that selects the path(s) pair(s) based on the end-toend SCC. We conduct extensive simulations considering realistic network topologies, and compare the performance of the SCCE-DRP scheme with the existing techniques. The obtained results show that, compared to the existing schemes, the SCC-E-DRP scheme achieves better results in terms of blocking probability.