scholarly journals Frequency-Dependent Friction in Transient Pipe Flow

1968 ◽  
Vol 90 (1) ◽  
pp. 109-115 ◽  
Author(s):  
W. Zielke
Keyword(s):  
Pipe Flow ◽  
Response Curve ◽  
Method Of Characteristics ◽  
Mean Velocity ◽  
Frequency Dependent ◽  
Velocity Changes ◽  
Transient Pipe Flow ◽  
Laminar Pipe Flow ◽  
Experimental Pressure ◽  
Theoretical Results

An equation is derived, which relates the wall shear stress in transient laminar pipe flow to the instantaneous mean velocity and to the weighted past velocity changes. The term is applied to the method of characteristics to calculate water-hammer phenomena in viscous fluids, in which effects of frequency-dependent friction cause distortion of traveling waves. Theoretical results are compared with the experimental pressure fluctuation due to an instantaneous valve closure and show accurate prediction of the response curve.

Frequency-dependent friction in oscillatory laminar pipe flow

1974 ◽  
Vol 16 (11) ◽  
pp. 819-827 ◽  
Author(s):  
D.A.P. Jayasinghe ◽  
M.S. Letelier ◽  
H.J. Leutheusser
Keyword(s):  
Pipe Flow ◽  
Frequency Dependent ◽  
Laminar Pipe Flow

Efficient Methods for Numerical Modeling of Laminar Friction in Fluid Lines

2006 ◽  
Vol 128 (4) ◽  
pp. 829-834 ◽  
Author(s):  
D. Nigel Johnston
Keyword(s):  
Computational Efficiency ◽  
Method Of Characteristics ◽  
High Accuracy ◽  
Slight Reduction ◽  
Improved Method ◽  
Frequency Dependent ◽  
Transmission Line Method ◽  
Laminar Pipe Flow ◽  
Very High ◽  
High Computational Efficiency

An improved method for simulating frequency-dependent friction in laminar pipe flow using the method of characteristics is proposed. It has a higher computational efficiency than previous methods while retaining a high accuracy. By lumping the frequency-dependent friction at the ends of the pipeline, the computational efficiency can be improved further, at the expense of a slight reduction in accuracy. The technique is also applied to the transmission line method and found to give a significant improvement in accuracy over previous methods, while retaining a very high computational efficiency.

Efficient Methods for Numerical Modelling of Laminar Friction in Fluid Lines

2004 ◽  
Author(s):  
D. Nigel Johnston
Keyword(s):  
Computational Efficiency ◽  
Method Of Characteristics ◽  
High Accuracy ◽  
Slight Reduction ◽  
Improved Method ◽  
Frequency Dependent ◽  
Transmission Line Method ◽  
Laminar Pipe Flow ◽  
Very High ◽  
High Computational Efficiency

An improved method for simulating frequency-dependent friction in laminar pipe flow using the Method of Characteristics (MOC) is proposed. It has a higher computational efficiency than previous methods whilst retaining a high accuracy. By lumping the frequency-dependent friction at the ends of the pipeline the computational efficiency can be improved further, at the expense of a slight reduction in accuracy. The technique is also applied to the Transmission Line Method (TLM) and found to give a significant improvement in accuracy over previous methods, whilst retaining a very high computational efficiency.

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