The Eighth Asia-Pacific Conference on Wind Engineering, December 10–14, 2013, Chennai, India CHARACTERISTICS OF TORNADO VORTEX DEVELOPED UNDER A TRANSLATING TORNADO-LIKE FLOW SIMULATOR G.R.Sabareesh 1 , Masahiro Matsui 2 , Yukio Tamura 3 1 Assistant Professor, Wind Engineering Application Centre, Jaypee University of Engineering & Technology India, sabareesh1981@gmail.com 2 Professor, Wind Engineering Research Centre, Tokyo Polytechnic University, Japan, matsui@arch.t- kougei.ac.jp 3 Professor, Wind Engineering Research Centre, Tokyo Polytechnic University, Japan, yukio@arch.t- kougei.ac.jp ABSTRACT Tornadoes are deadliest of all winds causing damage to life and property in many parts of the world. Their uncertainty and associated danger makes real time investigations difficult. In the past three decades attempts are made to simulate tornado-like flow in the laboratory and expose scaled building models to it. Many earlier attempts did not consider the translating effect of vortices. The present investigation explores the characteristics of the tornado like vortex developed using the translating tornado-like flow simulator at Tokyo Polytechnic University and the generated flow field surrounding it. Keywords: Tornado vortex, Tornado simulator, Flow visualization, pressure measurement, building models Introduction Tornadoes occur worldwide every year, causing damage to life and property. Recent investigations by Tamura (2011) give the statistics of number of tornadoes occurring per year in Japan as high as 35~40. Aerodynamic forces are induced on building structures exposed to a tornado resulting in damage of structures. Many researchers in the past such as Chang (1971) , Ward (1972), Jischke and Light (1983), Mishra et al. (2008), Sabareesh et al (2011,2012) have investigated the pressure distribution on scaled building models by exposing them to stationary vortex. Sarkar et al. (2005) developed a tornado like flow simulator which could mimic the nature’s violent vortex better by incorporating the translational effects. The new tornado like flow generator developed at Tokyo Polytechnic University is capable of generating translating vortices enabling a better understanding of the underlying phenomena of tornado-structure interaction such as the combined effects of translation and rotation of tornado vortex on surface and internal pressures on buildings exposed to it. A pre-requisite for this will involve characterizing the structure of the laboratory tornado and also the flow field developed around it. The present paper discusses in detail some of the measurements performed to determine the variation of velocity at any point in the ground as the tornado translates and also the variation of pressure at different points on the ground as the tornado translates. Proc. of the 8th Asia-Pacific Conference on Wind Engineering – Nagesh R. Iyer, Prem Krishna, S. Selvi Rajan and P. Harikrishna (eds) Copyright c  2013 APCWE-VIII. All rights reserved. Published by Research Publishing, Singapore. ISBN: 978-981-07-8011-1 doi:10.3850/978-981-07-8012-8 292 99