Sudan Engineering Society Journal, March 2008, Volume 54 No. 50 33 EVALUATION OF BUOYANT PLUME WITH NEW ASSUMPTION TO SIMULATE A REAL TURBULENT FLOW Sakhr B. Abu Darag and Khalid H. Sail Aeronautical Engineering Department, Engineering College, SUST, P.O. Box: 407, Khartoum, Sudan. Received Dec. 2006, accepted after revision Oct. 2007 ﺺ ـﻠـ ﺨ ــﺘ ـﺴ ﻣ ﺣﻘﻴﻘﻲ ﻣﻀﻄﺮب اﻧﺴﻴﺎب ﻟﻤﺤﺎآﺎة ﻣﺘﻤﻮج اﻧﺴﻴﺎب ﻋﻠﻰ أﺟﺮاؤهﺎ ﺗﻢ ﻣﻌﻤﻠﻴﺔ دراﺳﺔ اﻟﻮرﻗﺔ هﺬﻩ ﺗﺘﻨﺎول. اﻟﻤﻌﻤﻠﻴﺔ اﻟﻘﻴﺎﺳﺎت  ﻋﻤﻮدﻳﺎ ﺳﺎﺧﻦ هﻮاء ﻧﻔﺚ ﺑﻮاﺳﻄﺔ ﺗﻮﻟﻴﺪﻩ ﺗﻢ واﻟﺬي اﻟﻤﺘﻤﻮج اﻻﻧﺴﻴﺎب ﺣﻮل آﻬﺮﺑﻴﺔ ﻣﺤﺴﺎت ﻃﺮﻳﻖ ﻋﻦ ﺗﻤﺖ وﺳﻂ ﻓﻲ ﺳﺎآﻦ. آﻌﺎ ﻋﺎل رﻳﻨﻮﻟﺪز رﻗﻢ اﻋﺘﻤﺎد ﺗﻢ ذات ﺑﺎﺳﺘﺨﺪام أﺟﺮﻳﺖ ﺳﺎﺑﻘﺔ دراﺳﺔ ﻻﺧﺘﺒﺎر اﻟﻤﻀﻄﺮب ﻟﻼﻧﺴﻴﺎب أﺳﺎﺳﻲ ﻣﻞ اﻟﻮﺳﻴﻠﺔ. ﻳﻤﻜﻦ ﻻ اﻟﺤﺎﻟﻲ ﻃﺎﻗﺘﻪ ﺑﻤﺼﺪر اﻻﺧﺘﺒﺎر ﻹﺟﺮاء اﻟﻤﺴﺘﺨﺪم اﻟﺠﻬﺎز أن اﻟﻨﺘﺎﺋﺞ أوﺿﺤﺖ أ ﻳﺤﺎآ اﻧﺴﻴﺎب ﻳﻮﻟﺪ ن ﻲ و اﻟﻤﻀﻄﺮب اﻻﻧﺴﻴﺎب أ اﻟﻤﻨﺒﻊ ﻋﻨﺪ اﻟﺘﻌﻮﻳﻢ زﻳﺎدة ﻳﺘﻄﻠﺐ اﻟﺠﻬﺎز آﻔﺎءة زﻳﺎدة ن. ﻣﺼﺪر آﺬﻟﻚ ﻳﺴﺘﺒﺪل أن ﻻﺑﺪ اﻟﻘﺪرة اﻟﺴﺮﻋﺔ ﻗﻴﺎس إﺟﺮاء أﺛﻨﺎء اﻟﺤﺮارة درﺟﺔ ﻓﻲ اﻟﺘﺤﻜﻢ ﻳﺘﻢ ﺣﺘﻰ اﻟﻤﻘﺎوﻣﺎت ﻣﺘﻐﻴﺮ ﺑﺄﺧﺮ. ﻗﺮاءات ﻓﻲ اﻟﺘﻐﻴﺮ اﻋﺘﻤﺎد ﺗﻢ وﻣﻌﺎﻳﺮﺗ اﻻﺧﺘﺒﺎر إﺟﺮاء أﺛﻨﺎء اﻟﺤﺮارة ودرﺟﺎت اﻟﺴﺮﻋﺔ ﻪ ﻣﺨﺘﻠﻔﺔ ﺣﺮارة درﺟﺎت ﺛﻼث ﻋﻨﺪ. اﻟﺤﺮارة درﺟﺎت إﻳﺠﺎد ﺗﻢ ﺑﻴﻨﻤﺎ ﺗﺎﻳﻠﻮر ﻗﺎﻧﻮن ﻃﺮﻳﻖ ﻋﻦ ﻣﺴﺘﻮى ﻋﻨﺪ اﻟﺴﺮﻋﺎت ﻗﻴﺎس ﺗﻢm 1.3 اﻟﻤﻨﺒﻊ أﻋﻠﻰ. ABSTRACT This paper reports an experimental study on a buoyant plume in an attempt to simulate a real turbulent flow. The measurements are done by a set of hot and cold-wire around buoyant plume which was generated by forcing a jet of hot air vertically up into quiescent environment. High Reynolds number is considered as a main factor to evaluate an earlier study. The results indicate that the facility with the recent source power is not capable of simulating a real world and the increasing of the facility efficiency requires the increasing of the buoyancy added at the source (Fo). Also the constant power delivery must be replaced with a heat controller (of PIDR –type), which is able to keep the temperature at a constant level during the velocity measurements. The change in temperature and the velocity variation are considered in the measurements. The measurement conducted was a temperature-velocity calibration which is done at three different temperatures. The temperature field is measured using the Taylor expansion expression, whereas the velocity profile in spanwise direction is measured at 1.3 m above the plume. Keywords: Buoyant Plume, Constant Temperature Anemometer (CTA), Taylor expansion. Nomenclature: Latin D plume exit diameter Fr Froude number Fo Buoyancy at the source G gravity acceleration L integral scale Re Reynolds number Ts scaling temperature T ∞ ambient temperature U s scaling velocity Uo velocity at the centre V mean velocity V fluctuating velocity x distance in streamwise direction Greek Ρ density ν kinematics viscosity ε dissipation η spanwise similarity coordinate η k kolmogorov length scale