Rotorcraft blade-vortex interaction noise prediction using the Lattice-Boltzmann method

Abstract The aim of this paper is to assess the accuracy, capabilities and computational performances of the Lattice-Boltzmann/Very Large Eddy Simulation Method to predict the unsteady aerodynamic loads, the rotor wake development and the noise radiation of helicopter rotors in strong Blade-Vortex Interaction conditions. The numerical flow solution is obtained by solving the explicit, transient and compressible Lattice-Boltzmann equation implemented in the high-fidelity CFD/CAA solver Simulia PowerFLOW®. The acoustic far-field is computed by using the Ffwocs-Williams & Hawkings integral solution applied to a permeable surface encompassing the whole helicopter geometry. The employed benchmark configuration is the 40% geometrically and aeroelastically scaled model of a BO-105 4-bladed main rotor tested in the open-jet anechoic test section of the German-Dutch wind tunnel in the framework of the HART-II project. In the present study, only the baseline operating condition of the experimental campaign, without Higher-Harmonic Control enabled, is considered. All simulations are performed by assuming a rigid blade motion, but a computational strategy based on a combination of a rigid blade pitching motion and a transpiration velocity boundary condition applied on the blade surface is employed to take into account the blade elastic deformation motion measured during the experiments. As expected, modeling the blade elastic deformation leads to more accurate predictions of control settings, unsteady air-loads and noise footprint. The effects of the computational grid on the aerodynamic and aeroacoustic prediction is documented as well.

[1]  Berend G. van der Wall,et al.  Completion of SPR Data Analysis from HART II , 2004 .

[2]  Jinhee Jeong,et al.  On the identification of a vortex , 1995, Journal of Fluid Mechanics.

[3]  Berend G. van der Wall,et al.  HART-II: Prediction of Blade-Vortex Interaction Loading , 2003 .

[4]  B. Launder,et al.  The numerical computation of turbulent flows , 1990 .

[5]  C. Teixeira.  INCORPORATING TURBULENCE MODELS INTO THE LATTICE-BOLTZMANN METHOD , 1998 .

[6]  P. Bhatnagar,et al.  A Model for Collision Processes in Gases. I. Small Amplitude Processes in Charged and Neutral One-Component Systems , 1954 .

[7]  James D. Baeder,et al.  An Assessment of Comprehensive Code Prediction State-of-the-Art Using the HART II International Workshop Data , 2012 .

[8]  Berend G. van der Wall,et al.  An Assessment of CFD/CSD Prediction State-of-the-Art Using the HART II International Workshop Data , 2012 .

[9]  Giovanni Bernardini,et al.  Assessment of Computational Models for the Effect of Aeroelasticity on BVI Noise Prediction , 2007 .

[10]  Markus Raffel,et al.  The HART II Test in the LLF of the DNW - a Major Step towards Rotor Wake Understanding , 2002 .

[11]  Jayanarayanan Sitaraman,et al.  Aerodynamic and Aeroacoustic Prediction Methodologies with Application to the HART II Model Rotor , 2006 .

[12]  S. Orszag,et al.  Expanded analogy between Boltzmann kinetic theory of fluids and turbulence , 2004, Journal of Fluid Mechanics.

[13]  van der Wall,et al.  Mode identification and data synthesis of HART II blade deflection data - part II , 2007 .

[14]  D. Casalino.  An advanced time approach for acoustic analogy predictions , 2003 .

[15]  D. Casalino,et al.  Turbofan Broadband Noise Prediction Using the Lattice Boltzmann Method , 2016 .

[16]  D. L. Hawkings,et al.  Sound generation by turbulence and surfaces in arbitrary motion , 1969, Philosophical Transactions of the Royal Society of London. Series A, Mathematical and Physical Sciences.

[17]  Giovanni Bernardini,et al.  Rotorcraft Comprehensive Code Assessment for Blade-Vortex Interaction Conditions , 2018 .

[18]  E. Fares,et al.  Facing rim cavities fluctuation modes , 2013 .

[19]  S. Orszag,et al.  Extended Boltzmann Kinetic Equation for Turbulent Flows , 2003, Science.

[20]  G. P. Succi,et al.  The prediction of helicopter rotor discrete frequency noise , 1982 .

[21]  S. Orszag,et al.  Renormalization group analysis of turbulence. I. Basic theory , 1986 .

[22]  Hudong Chen,et al.  A Lattice-Boltzmann / Finite-Difference Hybrid Simulation of Transonic Flow , 2009 .

[23]  Matthaeus,et al.  Recovery of the Navier-Stokes equations using a lattice-gas Boltzmann method. , 1992, Physical review. A, Atomic, molecular, and optical physics.

[24]  E. Fares,et al.  Lattice–Boltzmann Aeroacoustic Analysis of the LAGOON Landing-Gear Configuration , 2014 .

[25]  E. Fares,et al.  Towards Full Aircraft Airframe Noise Prediction: Lattice Boltzmann Simulations , 2014 .

[26]  Berend G. van der Wall,et al.  The HART II international workshop: an assessment of the state-of-the-art in comprehensive code prediction , 2013 .

[27]  Yung H. Yu,et al.  Rotor blade–vortex interaction noise , 2000 .

[28]  David Freed,et al.  A Ffowcs Williams-Hawkings Solver for Lattice-Boltzmann based Computational Aeroacoustics , 2010 .

[29]  Berend G. van der Wall,et al.  The HART-II Test: Rotor Wakes and Aeroacoustics with Higher-Harmonic Pitch Control (HHC) Inputs - The Joint German/French/Dutch/US Project , 2002 .

[30]  van der Wall,et al.  2nd HHC Aeroacoustic Rotor Test (HART II) - Part I: Test Documentation - , 2003 .

[31]  Hudong Chen,et al.  Realization of Fluid Boundary Conditions via Discrete Boltzmann Dynamics , 1998 .

[32]  Leslie M. Smith,et al.  Renormalization group analysis of turbulence , 2003 .

[33]  Miss A.O. Penney.  (b) , 1974, The New Yale Book of Quotations.

[34]  G. Brès,et al.  Properties of the Lattice-Boltzmann Method for Acoustics , 2009 .

[35]  E. Fares,et al.  Evaluation of Airframe Noise Reduction Concepts via Simulations Using a Lattice Boltzmann Approach , 2015 .

[36]  D. Douglas Boyd,et al.  Hart-II Acoustic Predictions Using a Coupled Cfd/CSD Method , 2013 .

[37]  Berend G. van der Wall,et al.  The HART II international workshop: an assessment of the state of the art in CFD/CSD prediction , 2013 .

[38]  Berend G. van der Wall,et al.  Preparation of SPR Data from HART II - Final Analyzing Methods and Results - , 2003 .

[39]  S. Orszag,et al.  Development of turbulence models for shear flows by a double expansion technique , 1992 .

[40]  D. Casalino,et al.  Fan Tonal and Broadband Noise Simulations at Transonic Operating Conditions Using Lattice-Boltzmann Methods , 2018, 2018 AIAA/CEAS Aeroacoustics Conference.

[41]  Berend G. van der Wall,et al.  2nd HHC Aeroacoustic Rotor Test (HART II) - Part II: Representative Results - , 2005 .

[42]  Raoyang Zhang,et al.  Lattice Boltzmann Approach for Local Reference Frames , 2011 .