Document Type : Original Article

Authors

1 Iran Space Research Center

2 Iranian Space Research Center

Abstract

In this paper, the computational fluid dynamics simulation of a tactical aerostat is conducted and the longitudinal static coefficients of the aerostat are evaluated. In this simulation, Fluent software and Spalart- Allmaras turbulent model are used. First, in order to validate the numerical method and the applied turbulent model, a famous airship hull is simulated and the drag coefficient at zero angle of attack is compared with the references and the CD0 is in very good agreement with references. Then, the designed aerostat is simulated in the angle attack of )-10 to 30( degrees then the pressure, Y+ contours and the streamlines around the aerostat are presented. Furthermore, the aerodynamic longitudinal coefficients are calculated for 5 and 20 m/s. The results show that the aerodynamic coefficients do not vary significantly with the change of velocity and the pitch moment coefficient about the nose of the designed aerostat has a negative slope. Finally, Comparing the pitch moment coefficient of the designed aerostat with two American and Korean aerostats indicate that, the designed aerostat has more static stability.

Keywords

Main Subjects

##Chan and J. Hunt. “Wind tunnel study of a large aerostat.” 11th AIAA Aviation Technology, Integration, and Operations (ATIO) Conference, including the AIAA Balloon Systems Conference and 19th AIAA Lighter-Than. 2011.‏##
##Dexheimer, Tethered Balloon System (TBS) Instrument Handbook. No. DOE/SC-ARM-TR-206. DOE Office of Science Atmospheric Radiation Measurement (ARM) Program (United States), 2018.‏##
##Saleem, and M. H. Kim. "Aerodynamic analysis of an airborne wind turbine with three different aerofoil-based buoyant shells using steady RANS simulations." Energy Conversion and Management, Vol. 177, pp. 233-248.‏ 2018.##
##U. Vehicles and M. E. Rogers, “LIGHTWEIGHT AEROSTAT SYSTEM (LAS) A New Concept In Security Surveillance and Communications Relay,” 2009.##
##Bilaye, V. N. Gawande, U. B. Desai, A. A. Raina, and R. S. Pant, “Low cost wireless internet access for rural areas using tethered aerostats,” IEEE Reg. 10 Colloq. 3rd Int. Conf. Ind. Inf. Syst. ICIIS 2008, no. 06, pp. 6–10. 2008.##
##Smith, Steve, et al. “HiSentinel80: flight of a high altitude airship, 11th AIAA Aviation Technology.” Integration, and Operations (ATIO) Conference, Virginia Beach, VA. 2011.‏##
##P. Androulakakis and R. Judy, “Status and plans of high altitude airship (HAATM) program,” AIAA lighter than-air systems technology (LTA) conference, Daytona Beach, FL, USA, 2013.##
##Lutz, P. Funk, A. Jakobi, et al. “Summary of aerodynamic studies on the LOTTE airship,” Proceedings of the 4th international airship convention and exhibition, Cambridge, UK, 2002.##
##Funk, T. Lutz and S.Wagner, “Experimental investigations on hull-fin interferences of the LOTTE airship,” Aerospace Science Technology, 7, pp. 603–610. 2003.##
##Funk, A. Jakobi, T. Lutz, et al., “Experiments on the Flow field of an inclined airship body,” Proceedings of the international airship convention and exhibition, Friedrichshafen, Germany, 2000.##
##Suman, S. Lakshmipathy and R. S. Pant, “Evaluation of assumed-transition-point criterion in context of Reynolds-averaged simulations around lighter-than-air Vehicles,” J Aircraft, 50, pp. 450–456. 2011.##
##A. Kanoria, K. Panchal and R. Dongre, et al. “Computational modelling of aerodynamic characteristics of airships in arbitrary motion,” 22nd AIAA lighter-than-air systems technology conference, Dallas, TX, USA, 2015.##
##C. Chan, K. Shervington and J. Hunt, “Wind tunnel study of a large aerostat, CFD validation,” AIAA lighter-than-air systems technology (LTA) conference, Daytona Beach, FL, USA, 2013.##
##C. Chan SC and J. Hunt, “Wind tunnel study of a large aerostat,” AIAA 11th aviation, technology, integration, and operations conference and 19th lighter-than-air technology conference, Virginia Beach, VA, USA, 2011.##
##Xiao-liang, F. Gong-yi, and D. Deng-ping, “Experimental investigations on aerodynamic characteristics of the zhiyuan-1 airship,” Journal of Aircraft, vol. 47, pp. 1463-1468, 2010.##
##Joubert, , and R. Jean-François, “Open-Source CFD Code Assessment for Lighter-Than-Air Aerodynamic Flows Simulation,” 52nd 3AF International Conference on Applied Aerodynamics, 2017.##
##Voloshin, K. C. Yong, and K. C. Rajnish, “A comparison of turbulence models in airship steady-state CFD simulations,” arXiv preprint arXiv, pp. 1210.2970, 2012.##
##D. Reddy and R. S. Pant, “CFD analysis of‌axisymmetric bodies of revolution using OpenFOAM,” 2018 Applied Aerodynamics Conference, p. 333, .2018.##
##Lynn et. al., “Aerodynamic Design of KARI Mid-sized Aerostat,” KSAS International Journal, Vol, No 1, 2006.##