﻿ Numerical Simulation of Air Launch Aeroelasticity with Random Variation of Aerodynamic Loading Parameters | HERALD OF THE BAUMAN MOSCOW STATE STATE TECHNICAL UNIVERSITY
|

# Numerical Simulation of Air Launch Aeroelasticity with Random Variation of Aerodynamic Loading Parameters

 Authors: Tushev O.N., Shcheglov G.A. Published: 09.02.2015 Published in issue: #1(100)/2015 Category: Aviation and Rocket-Space Engineering | Chapter: Aerodynamics and Heat Transfer Processes in Aircrafts Keywords: air launch, aeroelasticity, vortex element method, structural dynamics, stochastic analysis

The problem of safe air launch vehicle descent from heavy airlifter cargo bay is considered. The influence of aircraft fuselage vortex wake on the descend dynamics is studied. Three-dimensional incompressible flow is considered. The coupled fluid - structure interaction problem is solved. Vortex element method with new vortex element - vortex cell for unsteady flow dynamic simulation is used. The elastic-mass model of the vehicle and launcher is taken into account. Aim of this work is to study influence of wake stochastic characteristics on the unsteady aerodynamic loads and on kinematic parameters of launch vehicle motion. Stochastic analysis method is used to define the boundaries of kinematic parameters’ variation region. The probability of hitting a random event into the region with boundaries is found to be almost equal to the probability of a certain event. An original algorithm with moderate computational cost is presented for determining the boundaries of the parameter variation region. Numerical simulation results are obtained for variation regions of linear and angular displacements boundary of heavy launch vehicle prototype. It is shown that random variation of the wakes initial state gives a significant variation region for kinematic parameters of the vehicle, not only in the pitch plane, but also in the yaw plane so that the worst-case combination of parameters can lead to emergency.

## References

[1] M. Sarigul-Klijn, N. Sarigul-Klijn, G. Hudson, L. Hoider, D. Fritz, C. Webber, G. Liesman, D. Shell, M.P. Gionfriddo. Flight Testing of a Gravity Air Launch Method to Enable Responsive Space Access. AIAA Paper 2007-6146, 2007.

[2] M. Sarigul-Klijn, N. Sarigul-Klijn, G.C. Hudson, and C. Brown. A New Air Launch Concept: Vertical Air Launch Sled (VALS). AIAA SPACE 2012 Conference and Exposition, AIAA Paper 2012-5156, 2012.

[3] Konyukhov S.N., Lynnyk A.K., Tonkonozhenko A.M. Concepts and problems in realization of air launch: Ukrainian aspect. 61st International Astronautical Congress 2010, IAC 2010, vol. 6, 2010, pp. 5068-5075.

[4] Bal’montB.V, Karpov A.S., IvanovR.K. Russian aerospace project "Air Launch". Polet. Obshcherossiiskii nauchno-tekhnicheskii zhurnal [Flight. All-Russian scientific and technical J.], 2012, no. 9, pp. 3-15 (in Russ.).

[5] Borisov A.V. Postroenie modeli vozmushchenii i analiz tochnosti vertikal’nogo manevra samoleta-nositelya pri desantirovanii rakety-nositelya. Diss.... kand. tekhn. nauk [Development of perturbation model and accuracy analysis of aircraft vertical maneuver by launch vehicle descent. Cand. tech. sci. diss.]. Moscow, 2006, 128 p. (in Russ.).

[6] Sikharulidze Yu.G., Ivanov R.K., Borisov A.V. Analiz poryvov vetra na uchastke vertikal’nogo manevra ("Gorka") samoleta-nositelya s tsel’yu desantirovaniya rakety-nositelya [Analysis of wind gusts loading by launch vehicle descent aircraft vertical maneuver (45 Up line)]. KIAM RAS, Moscow, Preprint no. 38, 2005, 24 p.

[7] Korotkiy S.A. Raschet proektnykh parametrov aerokosmicheskoi sistemy s vozdushnym startom s uchetom intensivnogo vikhreobrazovaniya. Diss.... kand. tekhn. nauk [Calculation of design parameters for air launch aerospace system subject to intense vorticity. Cand. tech. sci. diss.]. Moscow, 2010, 121 p. (in Russ.).

[8] Marchevsky I.K., Scheglov G.A. Symmetrical vortex fragmenton as a vortex element for incompressible 3D flow simulation (2011). Computational Fluid Dynamics 2010. Proceedings of the 6th International Conference on Computational Fluid Dynamics, ICCFD 2010, pp. 897-898. DOI: 10.1007/978-3-642-17884-9-119

[9] Shcheglov G.A. Application of vortons to calculate vibrations of a beam in spatial flow. Izv. RAN Problemy mashinostroeniya i nadezhnosti mashin [J. of Machinery Manufacture and Reliability], 2009, no. 38 (4), pp. 319-323 DOI: 10.3103/S1052618809040025

[10] Dynnikova G.Ya. The Integral Formula for Pressure Field in the Nonstationary Barotropic Flows of Viscous Fluid. J. Math. Fluid Mech., 2014, no. 16, pp. 145-162. DOI: 10.1007/s00021-013-0148-z

[11] Tushev O.N., Arinchev S.V. Defining the parameters of a mechanical system for a given reliability. Raschety naprochnost’ [Collect. pap. "Strength analysis"]. Moscow, Mashinostroenie Publ., 1985, vol. 26, pp. 183-195.

[12] Tushev O.N., Sychev M.P. Estimation of Domain Boundaries for Construction Quality Parameters Spread under Given Reliability. E-J. Dynamic Strength and Wear Resistance of Machines, 2001, no. 8, pp. 8-16.