Buvaneswari Jayaraman

Rotor Loads Prediction Using Helios: A Multisolver Framework for Rotorcraft Aeromechanics Analysis

This paper documents the prediction of UH-60A Black Hawk aerodynamic loading using the multisolver Computational Fluid Dynamics/Computational Structural Dynamics analysis framework for rotorcraft Helios for a range of critical steady forward flight conditions. Comparisons with available flight test data are provided for all of the predictions. The Helios framework combines multiple solvers and multiple grid paradigms (unstructured and adaptive Cartesian) such that the advantages of each paradigm is preserved. Further, the software is highly automated for execution and designed in a modular fashion to minimize the burden on both the users and developers. The technical approach presented herein provides details of all of the participant modules and the interfaces used for their integration into the software framework. The results composed of sectional aerodynamic loading and wake visualizations are presented. Solution-based adapative mesh refinement, a salient feature of the Helios framework, is explored fo...

Rotor Loads Prediction Using HELIOS: A Multi-Solver Framework for Rotorcraft CFD/CSD Analysis

We explore the use of the Helios high-fidelity rotorcraft simulation software for forward flight CFD/CSD simulation of the UH-60A rotorcraft, comparing computed results for three critical flight conditions. The approach used for moving-body CFD/CSD analysis in Helios applies Cartesian-based unsteady adaptive mesh refinement (AMR) for the off-body wake solution, and results with the enhanced wake solution are compared to traditional fixed off-body refinement. Results show airload predictions that are generally comparable to existing state-of-the-art CFD/CSD analysis codes. The enhanced wake resolution from AMR provides some improvement to vibratory airload predictions but the improvements are marginal.

Helios Prediction of Blade-Vortex Interaction and Wake of the HART II Rotor

In this paper, we present the validation of the multi-disciplinary rotorcraft simulation code Helios for its ability to predict the blade-vortex interactions(BVI) and the rotor wake in the descending flight. Helios uses a dual-mesh paradigm with unstructured mesh near the body and Cartesian mesh in the o-body. The trim of the rotorcraft and the elastic blade deformations are modeled using the loose-coupling with RCAS comprehensive model. Three test conditions baseline, minimum noise and minimum vibration are used for the validation. Helios predictions for the baseline case which has strong BVI on both the advancing and retreating side are compared to the measured data, OVERFLOW 2/CAMRAD II and FUN3D/CAMRAD II predictions. The minimum noise and minimum vibration case predictions are compared to the measured data. Helios predictions compare favorably with the current state-of-the art codes. Cartesian-based unsteady adaptive mesh refinement (AMR) is applied in the o-body flow field to understand the eect of AMR on the prediction of the wake field.

Extensible Software Engineering Practices for the Helios High-Fidelity Rotary-Wing Simulation Code

We describe software engineering practices applied to the Helios code, an integrated computational fluid dynamics and structural dynamics platform for rotorcraft simulations. Helios consists of a collection of legacy and new simulation components, that are integrated together using a Python-based infrastructure. Given its target use as a production platform, rigorous software development practices are used to enable ease of development, builds, testing, and maintenance. Specific elements discussed are the unique aspects related to the development of production quality Python-based scientific simulation software including a multi-platform build environment and the installation of consistent versions of all support software across disparate computer systems. In addition, we also discuss continuous integration and regression testing, automatic reporting of performance/memory usage and scalability analysis.