The influence of model surface roughness on wind loads of the RC chimney by comparing the full-scale measurements and wind tunnel simulations

2013 ◽  
Vol 16 (2) ◽  
pp. 137-156 ◽  
Author(s):  
Chern-Hwa Chen ◽  
Cheng-Hsin Chang ◽  
Yuh-Yi Lin
2021 ◽  
Author(s):  
Thomas G. Ivanco ◽  
Donald F. Keller ◽  
Jennifer L. Pinkerton

2016 ◽  
Vol 20 (6) ◽  
pp. 843-864 ◽  
Author(s):  
XX Cheng ◽  
L Zhao ◽  
YJ Ge ◽  
R Dong ◽  
C Demartino

Adding vertical ribs is recognized as a useful practice for reducing wind effects on cooling towers. However, ribs are rarely used on cooling towers in China since Chinese Codes are insufficient to support the design of rough-walled cooling towers, and an “understanding” hampers the use of ribs, which thinks that increased surface roughness has limited effects on the maximum internal forces that control the structural design. To this end, wind tunnel model tests in both uniform flow field with negligible free-stream turbulence and atmospheric boundary layer (ABL) turbulent flow field are carried out in this article to meticulously study and quantify the surface roughness effects on both static and dynamic wind loads for the purpose of improving Chinese Codes first. Subsequently, a further step is taken to obtain wind effects on a full-scale large cooling tower at a high Re, which are employed to validate the results obtained in the wind tunnel. Finally, the veracity of the model test results is discussed by investigating the Reynolds number (Re) effects on them. It has been proved that the model test results for atmospheric boundary layer flow field are all obtained in the range of Re-independence and the conclusions drawn from model tests and full-scale measurements basically agree, so most model test results presented in this article can be directly applied to the full-scale condition without corrections.


Author(s):  
Kenneth W. Van Treuren ◽  
Jason R. Gregg

The importance of renewable and alternative energy is rapidly gaining attention. A national goal of replacing 20% of the United States electricity generation with wind power by 2030 has been proposed but such an ambitious goal is dependent on many parameters. Improved aerodynamic performance of wind turbine blades is one parameter necessary to achieve this goal. Blade testing is traditionally done using 2D airfoils in a laboratory wind tunnel, developing the lift and drag coefficients, and then using this data to predict wind turbine blade performance. Dimensional analysis has been used successfully in design of rotating machinery such as pumps, developing a series of dimensionless pump parameters with which to scale a particular pump design to a larger or small size. These parameters lead to similarity or affinity laws which relate any two homologous states for two pumps that are geometrically and dynamically similar. Affinity laws could be applied to wind turbines however the conditions tested in the wind tunnel do not match what would be expected in a full scale wind machine. As with pumps, the laws would apply only if the model and full scale wind turbine would operate at identical Reynolds numbers and are exactly similar (i.e. relative surface roughness and tip conditions). Reynolds numbers in the model tests are smaller than those achieved by the actual wind turbines while the surface roughness of the model is generally larger. This leads to the need for empirical equations to predict performance. This paper examines current wind tunnel testing and the problems with scaling wind turbine blades. It also outlines a methodology to test 3-D model wind turbine blades in a wind tunnel. Blades are designed and manufactured according to existing criteria, mounted to a generator, and their performance is then tested in the wind tunnel. Challenges with wind tunnel testing as well as extrapolation of the wind tunnel data to actual applications will be addressed.


2021 ◽  
Vol 235 ◽  
pp. 112101
Author(s):  
Johnny Estephan ◽  
Changda Feng ◽  
Arindam Gan Chowdhury ◽  
Mauricio Chavez ◽  
Appupillai Baskaran ◽  
...  

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