Reynolds number independence of cross-ventilation flow in an ensuite room

Abstract

Global energy consumption has been severe and reducing energy demand through natural ventilation has become a significant energy conservation goal To ensure that the ventilation performance is expected it is increasingly common to conduct wind tunnel test and CFD simulations before developing new buildings However the scale model of the wind tunnel test is limited by the atmospheric boundary layer Therefore we need to use the Reynolds number similarity and the Reynolds number independence to complete the research However according to the research results of relevant literature it is found that in the case of low Reynolds number the Reynolds number independence is not apparent To know the trend of Reynolds number independence we will use the 1/10 scale and 1/20 scale models which are the standard ensuite room in Taiwan to conduct wind tunnel test Additionally the data obtained from the wind tunnel test is compared with the CFD result to prove the CFD’s reliability Then we use the CFD to simulate the lower Reynolds number to know the scope of application of the Reynolds number independence CFD result found that the Reynolds number independence is very obvious when the Reynolds number is higher than 200000 Furthermore we can know the local Reynolds number by the measuring point wind speed value and the length of the secondary flow path Reynolds number independence is very obvious when the local Reynolds number is higher than 20000

Date of Award	2020
Original language	English
Supervisor	Chi-ming Lai (Supervisor)