Toward improved aeromechanics simulations using recent advancements in scientific computing (original) (raw)
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Requirements for Next Generation Comprehensive Analysis of Rotorcraft
The unique demands of rotorcraft aeromechanics analysis have led to the development of software tools that are described as comprehensive analyses. The next generation of rotorcraft comprehensive analyses will be driven and enabled by the tremendous capabilities of high performance computing, particularly modular and scaleable software executed on multiple cores. Development of a comprehensive analysis based on high performance computing both demands and permits a new analysis architecture. This paper describes a vision of the requirements for this next generation of comprehensive analyses of rotorcraft. The requirements are described and substantiated for what must be included and justification provided for what should be excluded. With this guide, a path to the next generation code can be found.
Parallelization of a three-dimensional flow solver for Euler rotorcraft aerodynamics predictions
AIAA Journal, 1996
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 each processor is performed via message passing in the form of message passing interface subroutine calls. The most difficult portion of the TURNS algorithm to implement efficiently in parallel is the implicit time step using the lower-upper symmetric Gauss-Seidel (LU-SGS) algorithm. Two modifications of LU-SGS are proposed to improve the parallel performance. First, a previously introduced Jacobi-like method called data-parallel lower upper relaxation (DP-LUR) is used. Second, a new hybrid method is introduced that combines the Jacobi sweeping approach in DP-LUR for interprocessor communications and the symmetric Gauss-Seidel algorithm in LU-SGS for on-processor computations. The parallelized TURNS code with the modified implicit operator is implemented on two distributed-memory multiprocessor, the IBM SP2 and Thinking Machines CM-5, and used to compute the three-dimensional quasisteady and unsteady flowfield of a helicopter rotor in forward flight. Good parallel speedups with a low percentage of communication are exhibited by the code. The proposed hybrid algorithm requires less CPU time than DP-LUR while maintaining comparable parallel speedups and communication costs. Execution rates found on the IBM SP2 are impressive; on 114 processors of the SP2, the solution time of both quasisteady and unsteady calculations is reduced by a factor of about 12 over a single processor of the Cray C-90.
A Hybrid Multi-GPU/CPU Computational Framework for Rotorcraft Flows on Unstructured Overset Grids
21st AIAA Computational Fluid Dynamics Conference, 2013
The advent of General Purpose Graphics Processing Units (GPGPUs) has spawned a lot of interest in computing high resolution flows in a shorter span of time. In combination with existing parallel programming techniques such as MPI or openMP, one is able to obtain at least one order increase in speed-up for CFD applications on stationary grids. Due to a high throughput/cost ratio, GPUs are increasingly becoming popular among the CFD community. Flow fields on helicopter systems rank among one of the most challenging, and hence are computationally demanding to simulate. Further, presence of multiple bodies moving relative to each other require use of overset grid systems, which in turn, require efficient overset grid assembly methods to support the flow solution. In this context, a computational framework for flow simulation across multiple CPU cores and multiple GPUs has been developed and tested. It is shown that the overall wall-clock time for the simulation can be considerably reduced by using multiple GPU cards. The parallel GPU framework is initially tested using both explicit and implicit schemes for the flow past a sphere. Further, a two-blade hovering rotor test case adopted from literature is used to demonstrate the capability of the code towards simulating rotorcraft flows in a short span of time.
2000
This paper gives an overall overview of the Brite/EuRam project ROSAA (ROtorcraft Simulation with Advanced Aerodynamics) in which the first common European integrated simulation system, the ROSAA system, for the multidisciplinary numerical prediction of rotor phenomena has been developed. The ROSAA system is a software simulation environment in which specialist codes belonging to different disciplines (CFD, Grid Generation, Aeroacoustics, Dynamics and Aeroelasticity) are able to exchange data within numerical processes. This kind of tool, where comprehensive rotor codes are integrated with CFD technology (including grid generation and aerodynamic post-processing) and an easy link is established with sophisticated aeroacoustic codes, can not only lead to an improved numerical prediction of aerodynamic, aeroacoustic and aeroelastic rotor phenomena but it can also reduce, by means of a high degree of automation, the time and cost of bringing products to the market.
Application of the Helios Computational Platform to Rotorcraft Flowfields
48th AIAA Aerospace Sciences Meeting Including the New Horizons Forum and Aerospace Exposition, 2010
This article describes the architecture, components, capabilities, and validation of the first version of the Helios platform, targeted towards rotorcraft aerodynamics. Capabilities delivered in the first version include fuselage aerodynamics with and without momentumdisk rotor models, and isolated rotor dynamics for ideal hover and forward flight coupled with aeroelasticity and trim. Helios is based on an overset framework that employs unstructured mixed-element meshes in the near-body domain combined with high-order Cartesian meshes in the off-body domain. In addition, the aerodynamics solution is coupled with structural dynamics and trim using a delta-coupling algorithm. The near-body CFD, offbody CFD, CSD and trim modules are coupled using a Python infrastructure that controls the execution sequence of the solution procedure. Specific validation studies presented include the Slowed Rotor Compound fuselage, Georgia Tech rotor body, TRAM rotor in hover and UH-60A rotor in forward flight. In all cases, Helios predictions are compared with experimental data and other state-of-the-art codes to demonstrate the accuracy, efficiency and scalability of the code.
GPU-accelerated simulations for eVTOL aerodynamic analysis
AIAA SCITECH 2023 Forum, 2023
The demand for fast, high-fidelity, scale-resolving computational fluid dynamics (CFD) simulations is continuously growing. Especially new emerging aviation technologies, such as electrical vertical takeoff and landing aircraft (eVTOL), strongly rely on advanced numerical methods to retain development life-cycle costs and achieving design targets more quickly. This paper presents a cutting-edge large-eddy simulations (LES) solver developed to enable overnight turnaround times for full aircraft simulations on advanced graphics processing unit (GPU) architectures. The solver models weakly compressible fluid flows over complex three-dimensional bodies based on an immersed boundary method with geometry-based and flow-based automatic mesh adaption. Its high accuracy and unprecedented performance is demonstrated for high Reynolds number aerodynamic benchmark cases and compared to recent results from literature. In addition, the successful validation against experimental data for the Lilium Jet canard is discussed.
An Assessment of the State-of-the-art in Multidisciplinary Aeromechanical Analyses
2008
: This paper presents a survey of the current state-of-the-art in multidisciplinary aeromechanical analyses which integrate advanced Computational Structural Dynamics (CSD) and Computational Fluid Dynamics (CFD) methods. The application areas to be surveyed include fixed wing aircraft, turbomachinery, and rotary wing aircraft. The objective of the authors in the present paper -- together with a companion paper on requirements -- is to lay out a path for a High Performance Computing (HPC) based next generation comprehensive rotorcraft analysis. From this survey of the key technologies in other application areas it is possible to identify the critical technology gaps that stem from unique rotorcraft requirements.
Overview of the Helios Version 2.0 Computational Platform for Rotorcraft Simulations
49th AIAA Aerospace Sciences Meeting including the New Horizons Forum and Aerospace Exposition, 2011
This article summarizes the capabilities and development of the Helios version 2.0, or Shasta, software for rotary wing simulations. Specific capabilities enabled by Shasta include off-body adaptive mesh refinement and the ability to handle multiple interacting rotorcraft components such as the fuselage, rotors, flaps and stores. In addition, a new run-mode to handle maneuvering flight has been added. Fundamental changes of the Helios interfaces have been introduced to streamline the integration of these capabilities. Various modifications have also been carried out in the underlying modules for near-body solution, off-body solution, domain connectivity, rotor fluid structure interface and comprehensive analysis to accommodate these interfaces and to enhance operational robustness and efficiency. Results are presented to demonstrate the mesh adaptation features of the software for the NACA0015 wing, TRAM rotor in hover and the UH-60A in forward flight.
Development of computer codes for analysis of rotorcraft aerodynamics
1986
Develop a 3-D Flow Solver for predicting the dynamic stall characteristics of airfoils, with a proper account of compressibility, sweep and turbulence. 2) Modify a full potential solver (RFS2) to account for 3-D Blade-Vortex Interaction. 3) Modify this solver to account for weak viscous effects.