Graphical Solution of Fluid-Friction Problems

1942 ◽  
Vol 9 (2) ◽  
pp. A82-A84
Author(s):  
E. S. Dennison
Keyword(s):  
Experimental Data ◽  
Reynolds Number ◽  
Friction Coefficient ◽  
Analytical Methods ◽  
Trial And Error ◽  
Graphical Solution ◽  
Fluid Friction

Abstract It is customary to present fluid-friction data in the form of a diagram to log scale in which friction coefficient appears as a function of Reynolds number. Such data are widely applicable to physical circumstances other than those which pertained to the original experiments. The present paper describes a graphical procedure for utilizing data of this character, where analytical methods are not practicable, and resort is made to trial-and-error methods. Similar methods to that described may be found useful in other fields than that of fluid friction, provided the experimental data are capable of being represented in nondimensional form.

A Study of Flow of Plastics Through Pipes

1946 ◽  
Vol 13 (2) ◽  
pp. A101-A105
Author(s):  
R. C. Binder ◽  
J. E. Busher
Keyword(s):  
Experimental Data ◽  
Reynolds Number ◽  
Friction Coefficient ◽  
Laminar Flow ◽  
Turbulent Flow ◽  
Dynamic Viscosity ◽  
Apparent Viscosity ◽  
Turbulent Viscosity ◽  
Yield Value

Abstract The pipe friction coefficient for true fluids is usually expressed as a function of Reynolds number. This method of organizing data has been extended to tests on the flow of different suspensions which behaved as ideal plastics in the laminar-flow range and as true fluids in the turbulent-flow range. In the laminar-flow range, Reynolds number below about 2100, the denominator in Reynolds number is taken as the apparent viscosity. The apparent viscosity can be determined from the yield value and the coefficient of rigidity. In the turbulent-flow range, the denominator in Reynolds number is an equivalent or turbulent viscosity equal to the dynamic viscosity of a true fluid having the same friction coefficient, velocity, diameter, and density as that of the plastic. The various experimental data on plastics correlate well with this extension of the method for true fluids.

Convective Inertia Effects in the Viscoseal

1974 ◽  
Vol 96 (3) ◽  
pp. 443-448 ◽  
Author(s):  
R. A. Meric ◽  
N. A. Macken
Keyword(s):  
Experimental Data ◽  
Reynolds Number ◽  
Friction Coefficient ◽  
Aspect Ratio ◽  
Side Wall ◽  
Reynolds Numbers ◽  
Present Theory ◽  
Inertia Effects ◽  
Critical Reynolds Numbers ◽  
Better Than

The performance characteristics of viscoseals are analyzed including the effects of convective inertia and the groove side wall. For the geometries studied, the present theory correlates the experimental data for the sealing and friction coefficient better than previous theories. The sealing coefficient is found to be dependent on the Reynolds number and groove width-to-depth aspect ratio. Leakage and critical Reynolds numbers are also discussed.

scholarly journals Fibre-induced drag reduction

2008 ◽  
Vol 602 ◽  
pp. 209-218 ◽  
Author(s):  
J. J. J. GILLISSEN ◽  
B. J. BOERSMA ◽  
P. H. MORTENSEN ◽  
H. I. ANDERSSON
Keyword(s):  
Experimental Data ◽  
Numerical Simulation ◽  
Reynolds Number ◽  
Drag Reduction ◽  
Elastic Layer ◽  
Turbulent Drag Reduction ◽  
Rigid Polymer ◽  
Fibre Concentration ◽  
Induced Drag ◽  
Turbulent Drag

We use direct numerical simulation to study turbulent drag reduction by rigid polymer additives, referred to as fibres. The simulations agree with experimental data from the literature in terms of friction factor dependence on Reynolds number and fibre concentration. An expression for drag reduction is derived by adopting the concept of the elastic layer.

Separation in oscillating laminar boundary-layer flows

1971 ◽  
Vol 47 (1) ◽  
pp. 21-31 ◽  
Author(s):  
R. A. Despard ◽  
J. A. Miller
Keyword(s):  
Experimental Data ◽  
Boundary Layer ◽  
Experimental Investigation ◽  
Reynolds Number ◽  
Reverse Flow ◽  
Oscillation Amplitude ◽  
Hot Wire ◽  
Boundary Layer Flows ◽  
Laminar Boundary Layers ◽  
History Of

The results of an experimental investigation of separation in oscillating laminar boundary layers is reported. Instantaneous velocity profiles obtained with multiple hot-wire anemometer arrays reveal that the onset of wake formation is preceded by the initial vanishing of shear at the wall, or reverse flow, throughout the entire cycle of oscillation. Correlation of the experimental data indicates that the frequency, Reynolds number and dynamic history of the boundary layer are the dominant parameters and oscillation amplitude has a negligible effect on separation-point displacement.

Difference in Critical Reynolds Number Between Hagen-Poiseuille and Plane Poiseuille Flows

2001 ◽  
Author(s):  
Hidesada Kanda
Keyword(s):  
Experimental Data ◽  
Reynolds Number ◽  
Poiseuille Flow ◽  
Average Velocity ◽  
Critical Reynolds Number ◽  
Inlet Section ◽  
Parallel Plates ◽  
Plane Poiseuille Flow ◽  
Contraction Ratio ◽  
Significant Difference

Abstract For plane Poiseuille flow, results of previous investigations were studied, focusing on experimental data on the critical Reynolds number, the entrance length, and the transition length. Consequently, concerning the natural transition, it was confirmed from the experimental data that (i) the transition occurs in the entrance region, (ii) the critical Reynolds number increases as the contraction ratio in the inlet section increases, and (iii) the minimum critical Reynolds number is obtained when the contraction ratio is the smallest or one, and there is no-shaped entrance or straight parallel plates. Its value exists in the neighborhood of 1300, based on the channel height and the average velocity. Although, for Hagen-Poiseuille flow, the minimum critical Reynolds number is approximately 2000, based on the pipe diameter and the average velocity, there seems to be no significant difference in the transition from laminar to turbulent flow between Hagen-Poiseuille flow and plane Poiseuille flow.

Strouhal number of flat and flapped plates at moderate Reynolds number and different angles of attack: experimental data

2018 ◽  
Vol 230 (1) ◽  
pp. 333-349 ◽  
Author(s):  
Ali Bakhshandeh Rostami ◽  
Mohammad Mobasheramini ◽  
Antonio Carlos Fernandes
Keyword(s):  
Experimental Data ◽  
Reynolds Number ◽  
Strouhal Number ◽  
Moderate Reynolds Number

Pressure, Frictional Resistance, and Flow Characteristics of the Partially Wetted Rotating Disk

1968 ◽  
Vol 90 (2) ◽  
pp. 395-404 ◽  
Author(s):  
H. N. Ketola ◽  
J. M. McGrew
Keyword(s):  
Experimental Data ◽  
Reynolds Number ◽  
Pressure Gradient ◽  
Flow Characteristics ◽  
Frictional Resistance ◽  
Rotating Disk ◽  
Practical Applications ◽  
Stationary Wall ◽  
Spacing Ratio ◽  
Analytical Expressions

A theory of the partially wetted rotating disk is described and experimental data presented which verify the application of this theory in practical applications. Four different flow regimes may be identified according to the value of the disk Reynolds number and the spacing ratio between the disk and stationary wall. The analytical expressions for prediction of the pressure gradient developed and the frictional resistance are uniquely determined by the disk Reynolds number, spacing ratio, and the degree of wetting of the disk.

scholarly journals EFFECT OF FRICTION ON VIBRATIONAL CHARACTERISTICS OF ROTOR SYSTEM DURING ROTOR-STATOR INTERACTION

2020 ◽  
pp. 22-31
Author(s):  
Anton Kurakin ◽  
Keyword(s):  
Experimental Data ◽  
Experimental Investigation ◽  
Friction Coefficient ◽  
Rotor System ◽  
Aluminum Bronze ◽  
Rotor Systems ◽  
Vibrational Characteristics ◽  
Rotor Stator Interaction ◽  
Intermediate Value ◽  
Impact Motion

Systems operation which include rotating elements in certain cases is associated with occurrence of contact between the rotating parts (rotor) and the stationary parts (stator). There were cases then rotor-stator interaction led to damage or to complete unit destruction. For this reason, rotor-stator interaction is one of the main problem of rotor systems exploitation. The main aim of the work is to gather detail data about effect of friction on vibrational characteristics of rotor system during rotor-stator interaction. In this article the experimental investigation method and experimental investigation of dynamic behavior of rotor during rotor-stator interaction is presented. The analysis of experimental data obtained during interaction between steel rotor and stator made of aluminum, bronze and PTFE is presented. All results with rotor-stator contact and without were compared by using Campbell diagrams, orbits and frequency responses. Analysis of experimental data shows that friction has strong effect on vibrational characteristics of rotor system during rotor-stator interaction. According to friction ratio three kinds of vibrational characteristics of rotor system are distinguished: forward slipping if friction coefficient is small, backward rolling if friction coefficient is big, vibratory impact motion if friction coefficient has intermediate value. Created experimental method and gathered data about rotor dynamics during rotor-stator contact can be used for verification and tuning of mathematical models.

scholarly journals Modelling of Friction Coefficient for Shoes Type LL By Means of Polynomial Fitting

2018 ◽  
Vol 12 (1) ◽  
pp. 114-127 ◽  
Author(s):  
L. Cantone ◽  
A. Ottati
Keyword(s):  
Experimental Data ◽  
Friction Coefficient ◽  
Input Data ◽  
Normal Force ◽  
Loading Conditions ◽  
Polynomial Fitting ◽  
Maximum Acceleration ◽  
Stopping Distance ◽  
Freight Traffic ◽  
Brake Cylinder

Introduction: The paper describes the automatic procedure, implemented in UIC software TrainDy, for the simulation of friction coefficient of new LL shoes, used to avoid noise from freight traffic. Method: This procedure uses certified experimental data obtained at dynamometer bench as input data and computes a series of polynomials laws that describe the evolution of friction coefficient with speed, for different values of normal force between brake blocks and wheel and for different initial braking speeds. Result: Numerical results are compared against two series of experimental slip tests, carried on Trenitalia freight wagons, in terms of both stopping distances (for different starting speeds and loading conditions) and pressure in brake cylinder, speed and acceleration. Errors in terms of stopping distance are always below 5% whereas errors in terms of maximum acceleration are up to 20%.

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