Measurements of the complex dynamic shear compliance and loss tangent of pilot whale blubber and the role of blubber in flow‐noise reduction

1990 ◽  
Vol 87 (S1) ◽  
pp. S147-S147 ◽  
Author(s):  
James W. Fitzgerald ◽  
Edwin R. Fitzgerald
Keyword(s):  
Noise Reduction ◽  
Loss Tangent ◽  
Dynamic Shear ◽  
Complex Dynamic ◽  
Pilot Whale ◽  
Flow Noise ◽  
Shear Compliance

scholarly journals Noise Reduction Effect of Superhydrophobic Surfaces with Streamwise Strip of Channel Flow

2021 ◽  
Vol 11 (9) ◽  
pp. 3869
Author(s):  
Chen Niu ◽  
Yongwei Liu ◽  
Dejiang Shang ◽  
Chao Zhang
Keyword(s):  
Reynolds Number ◽  
Drag Reduction ◽  
Noise Reduction ◽  
Channel Flow ◽  
Superhydrophobic Surface ◽  
Sound Field ◽  
Flow Noise ◽  
Slip Boundary ◽  
Eddy Simulation ◽  
Reduction Effect

Superhydrophobic surface is a promising technology, but the effect of superhydrophobic surface on flow noise is still unclear. Therefore, we used alternating free-slip and no-slip boundary conditions to study the flow noise of superhydrophobic channel flows with streamwise strips. The numerical calculations of the flow and the sound field have been carried out by the methods of large eddy simulation (LES) and Lighthill analogy, respectively. Under a constant pressure gradient (CPG) condition, the average Reynolds number and the friction Reynolds number are approximately set to 4200 and 180, respectively. The influence on noise of different gas fractions (GF) and strip number in a spanwise period on channel flow have been studied. Our results show that the superhydrophobic surface has noise reduction effect in some cases. Under CPG conditions, the increase in GF increases the bulk velocity and weakens the noise reduction effect. Otherwise, the increase in strip number enhances the lateral energy exchange of the superhydrophobic surface, and results in more transverse vortices and attenuates the noise reduction effect. In our results, the best noise reduction effect is obtained as 10.7 dB under the scenario of the strip number is 4 and GF is 0.5. The best drag reduction effect is 32%, and the result is obtained under the scenario of GF is 0.8 and strip number is 1. In summary, the choice of GF and the number of strips is comprehensively considered to guarantee the performance of drag reduction and noise reduction in this work.

New Directions in the Study of Institutional Logics: From Tools to Phenomena

2021 ◽  
Vol 47 (1) ◽  
Author(s):  
Michael Lounsbury ◽  
Christopher W.J. Steele ◽  
Milo Shaoqing Wang ◽  
Madeline Toubiana
Keyword(s):  
Recent Work ◽  
Online Publication ◽  
Institutional Logics ◽  
Annual Review ◽  
Publication Date ◽  
Complex Dynamic ◽  
New Directions ◽  
Analytical Tools ◽  
Dynamic Phenomena

In this article, we take stock of the institutional logics perspective and highlight opportunities for new scholarship. While we celebrate the growth and generativity of the literature on institutional logics, we also note that there has been a troubling tendency in recent work to use logics as analytical tools, feeding disquiet about reification and reductionism. Seeding a broader scholarly agenda that addresses such weaknesses in the literature, we highlight nascent efforts that aim to more systematically understand institutional logics as complex, dynamic phenomena in their own right. In doing so, we argue for more research that probes how logics cohere and endure by unpacking the role of values, the centrality of practice, and the governance dynamics of institutional logics and their orders. Furthermore, we encourage bridging the study of institutional logics with various literatures, including ethnomethodology, phenomenology, professions, elites, world society, and the old institutionalism, to enhance progress in these directions. Expected final online publication date for the Annual Review of Sociology, Volume 47 is July 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Research on acoustic behaviors of water pipelines with guide vanes

2022 ◽  
pp. 107754632110623
Author(s):  
Xianzhong Wang ◽  
Ning Li ◽  
Min Yu ◽  
Hongzhou Lin ◽  
Lili Ye
Keyword(s):  
Noise Reduction ◽  
Guide Vane ◽  
Experimental Methods ◽  
Guide Vanes ◽  
Experimental Platform ◽  
Flow Noise ◽  
Water Pipelines ◽  
Flow Speeds ◽  
Radiation Noise ◽  
Reduction Effect

In this paper, the pipeline with guide vanes was taken as the research object, the flow noise was studied based on the hybrid calculation method, then the acoustic-structure coupling method was introduced to study the vibration and radiation noise, and then explored the best position of the guide vanes. Based on the pipeline experimental platform and improved experimental methods, it was found that the guide vanes had a better noise reduction effect on the elbows; based on that, a simulation study was carried out on the elbow with guide vanes, and the mechanism of the guide vanes on the velocity field and pulsating pressure of the pipeline was explored. Finally, the noise reduction effect at different positions of the guide vanes under different flow speeds was studied. The results indicated that the guide vane at the middle of the elbow had the best effect on improving the flow field and reducing noise in the working conditions studied in this article, providing a calculation basis for the design of the guide vane.

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