TRANSACTIONS OF THE KRYLOV STATE RESEARCH CENTRE

Science journal

 
ISSN (print) 2542-2324 /(online) 2618-8244


Articles of The Transactions of KSRC








Specific features of coordinated variations in friction resistance and flow velocity profile in tubes at Toms effect



Full text article ( in russian)

Year

 
2021

Issue

 
397

Volume

 
3

Pages

 
25-32

Caption

 
Specific features of coordinated variations in friction resistance and flow velocity profile in tubes at Toms effect

Authors

 
Pavlovsky V., Orlov О.

Keywords

 
circular cylinder tube, flow conditions, Reynolds number, law of resistance, universal velocity profile, Prandtl – Nikuradze formula, Toms effect

DOI

 
10.24937/2542-2324-2021-3-397-25-32

Summary

 
Object and purpose of research. Relationships between friction resistance coefficient and velocity distributions in the turbulent boundary layer of low-concentrated polymer solutions are investigated. These relationships are different from water because in polymer solutions the friction resistance at constant Reynolds numbers is additionally changed with solution concentrations.
Subject matter and methods.The known experimental data on variations of the friction resistance coefficient and the velocity profiles in turbulent flows in circular tubes at changes in polymer solution concentrations
Main results. The general law of coordinated variations in friction resistance coefficient λ and flow velocity profile in the turbulent boundary layer depending on Reynolds number and polymer solution concentration. The flow models are validated, which describe the laws of velocity variations in all characteristic sections of boundary layer: laminar sublayer, buffer and logarithmic flow areas. A new non-dimensional number is introduced, which characterizes the ability of low concentrated water solutions of polymers to reduce the friction resistance. It is called the Toms effect parameter in the work.
Conclusion. Results of the investigation will be useful in developing the theoretical methods for estimation of boundary layer characteristics in polymer solutions

Rubrics

 
Naval architecture

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ISSN (print) 2542-2324 / ISSN (online) 2618-8244

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