REPUBLIC OF SERBIA

MINISTRY OF DEFENCE

www.mod.gov.rs

MINISTRY OF DEFENCE

Material Resources Sector

Defensive Technologies Department

Military Technical Institute

www.vti.mod.gov.rs

MEASUREMENT accuracy of flow-field parameters in a supersonic Wind-Tunnel environment

Dijana Damljanović

Military Technical Institute, Belgrade, Serbia,  didamlj@gmail.com

Đorđe Vuković

Military Technical Institute , Belgrade, Serbia,  vdjole@sbb.rs

Boško Rašuo

University of Belgrade, Faculty of Mechanical Engineering, Belgrade, Serbia,  brasuo@mas.bg.ac.rs

Jovan Isaković

Tehnikum Taurunum, College of Applied Engineering Studies, Belgrade, Serbia, jisakovic@tehnikum.edu.rs

Goran Ocokoljić

Military Technical Institute , Belgrade, Serbia,  ocokoljic.goran@gmail.com

Abstract: Complexity and interaction of different phenomena, which exist in the supersonic wind-tunnel testing, required defining an improved methodology for measurement of the relevant flow-field parameters of the increased accuracy level in the T-38 blowdown wind-tunnel of the Military Technical Institute (VTI) in Belgrade. Existing methodologies and all the factors which facilitate or make difficult the use of some methods had been studied and, based on these, the optimal methodology of measurement was defined and the primary measuring system was improved in accordance with specifications of the T-38 wind-tunnel in supersonic flow conditions. The research was based on 1) theoretical analisys of possibility to improve accuracy of measurement of supersonic flow-field parameters and 2) analysis of experimental results of a certain number of measurements in a framework of new-implemented primary measuring system. Verification of the research of the theoretical-methodical improvements of the measurement accuracy of supersonic flow-field parameters in wind-tunnels of the T-38 type was done in testing of a supersonic-hypersonic model of the standard geometry and obtained results were compared with those from initial testing before fine-tuning of the supersonic test section. As the VTI’s standard testing procedure insist on inter-facility comparisons, the test-data were also correlated with those from the worlds’ relevant supersonic wind-tunnels.

Keywords: wind-tunnel, supersonic flow-field, primary measuring system, Mach number, standard model, inter-facility correlations.