Predicting sound levels generated by jet fan ventilation systems in tunnels

2021 ◽  
pp. 261-289
Author(s):  
Michael J B Lotinga ◽  
Ben Saunders ◽  
Gennaro Sica
2013 ◽  
Vol 325-326 ◽  
pp. 310-314 ◽  
Author(s):  
Di Lin Pan ◽  
Kai Chen

Jet fans are widely used in ventilation systems of road tunnels, railway tunnels and subways etc. It was demonstrated that the static pressure generated by jet fan impeller is merely useful for overcoming its own internal flow resistance and can not improve the ventilation state of tunnel. It was pointed out that in the aerodynamic design process, the static pressure of jet fan should be made as small as possible. The effective way to reduce static pressure produced by impeller is the rational design of jet fan passage components.


Author(s):  
Mariia Sergeevna Rostova ◽  
Elizaveta Albertovna Saifullina ◽  
Inna Ivanovna Sukhanova
Keyword(s):  

2015 ◽  
Vol 39 (2) ◽  
pp. 199-202
Author(s):  
Wojciech Batko ◽  
Renata Bal

Abstract The assessment of the uncertainty of measurement results, an essential problem in environmental acoustic investigations, is undertaken in the paper. An attention is drawn to the - usually omitted - problem of the verification of assumptions related to using the classic methods of the confidence intervals estimation, for the controlled measuring quantity. Especially the paper directs attention to the need of the verification of the assumption of the normal distribution of the measuring quantity set, being the base for the existing and binding procedures of the acoustic measurements assessment uncertainty. The essence of the undertaken problem concerns the binding legal and standard acts related to acoustic measurements and recommended in: 'Guide to the expression of uncertainty in measurement' (GUM) (OIML 1993), developed under the aegis of the International Bureau of Measures (BIPM). The model legitimacy of the hypothesis of the normal distribution of the measuring quantity set in acoustic measurements is discussed and supplemented by testing its likelihood on the environment acoustic results. The Jarque-Bery test based on skewness and flattening (curtosis) distribution measures was used for the analysis of results verifying the assumption. This test allows for the simultaneous analysis of the deviation from the normal distribution caused both by its skewness and flattening. The performed experiments concerned analyses of the distribution of sound levels: LD, LE, LN, LDWN, being the basic noise indicators in assessments of the environment acoustic hazards.


2020 ◽  
Vol 781 (6) ◽  
pp. 50-53
Author(s):  
M.Yu. LESHKO ◽  
◽  
A.V. SIDORINA ◽  
A.V. VARGASOV ◽  
P.A. KOSHEEV ◽  
...  

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