Anastasios S. Lyrintzis

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An approach for parallelizing the three-dimensional Euler/Navier-Stokes rotorcraft computational fluid dynamics flow solver transonic unsteady rotor Navier-Stokes (TURNS) is introduced. Parallelization is performed using a domain decomposition technique that is developed for distributed-memory parallel architectures. Communication between the subdomains on(More)
A parallel genetic algorithm (GA) was used to generate, in a single run, a family of aerodynamically efficient, low-noise rotor blade designs representing the Pareto optimal set. The n-branch tournament, uniform crossover genetic algorithm operates on twenty design variables, which constitute the control points for a spline representing the airfoil surface.(More)
This paper compares two methods for predicting transonic rotor noise for helicopters in hover and forward ight. Both methods rely on a computational uid dynamics (CFD) solution as input to predict the acoustic near and far elds. For this work, the same full-potential rotor code has been used to compute the CFD solution for both acoustic methods. The rst(More)
When powerful machines such as the Cray-2 became available in the late 1980s, a number of researchers investi-We investigate the use of an inexact Newton's method to solve the potential equations in the transonic regime. As a test case, gated use of exact Newton's method for solving steady we solve the two-dimensional steady transonic small disturbance(More)
Computational aeroacoustics (CAA) has emerged as a tool to complement theoretical and experimental approaches for robust and accurate prediction of sound levels from aircraft airframes and engines. CAA, unlike computational fluid dynamics (CFD), involves the accurate prediction of small-amplitude acoustic fluctuations and their correct propagation to the(More)
The performance of two popular turbulence models, the Spalart-Allmaras model and Menter's SST model, and one relatively new model, Olsen & Coakley's Lag model, are evaluated using the OVERFLOW code. Turbulent shock-boundary layer interaction predictions are evaluated with three different experimental datasets: a series of 2D compression ramps at Mach 2.87,(More)
The modi cation of unsteady three-dimensional Navier–Stokes codes for application on massively parallel and distributed computing environments is investigated. Previously, the Euler mode of the Navier–Stokes code TURNS has been parallelized. For the eff cient implementation of the Navier–Stokes mode of TURNS on parallel computing systems, several(More)
Recently, there has been great interest in developing technologies that may enable a morphing aircraft. Such an aircraft can change shape in flight, which would make it possible to adjust the wing to the best possible shape for any flight condition encountered by the aircraft. However, there is an actuation cost associated with making these shape changes(More)