Clap and Fling Aerodynamics-An Experimental Evaluation

1977 ◽  
Vol 69 (1) ◽  
pp. 261-272 ◽  
Author(s):  
LEON BENNETT
Keyword(s):  
Reynolds Number ◽  
Experimental Evaluation ◽  
Model Form ◽  
Aerodynamic Effect ◽  
Lift Index ◽  
Induced Velocity

The ‘Clap and Fling’ hypothesis, which describes augmentation of lift during the wingbeat of certain insects and birds, was evaluated experimentally in model form. Using induced velocity output as a lift index, and testing at a Reynolds number of roughly 83000, it was learned that: 1. The main ‘Clap and Fling’ aerodynamic effect consists of raising the lift output realized at the beginning of the stroke. After one chord of travel, ‘Clap and Fling’ effects are minor.2. Considered over a complete stroke, ‘Clap and Fling’ lift output is limited to 1.15 times the lift output of an identical fixed incidence wing undergoing the same jump start trajectory.3. ‘Clap and Fling’ output is limited by considerations of maximum circulation and circulation persistence. These limitations are not envisioned in current analyses.

Experimental evaluation of the mean momentum and kinetic energy balance equations in turbulent pipe flows at high Reynolds number

2019 ◽  
Vol 20 (5) ◽  
pp. 285-299 ◽  
Author(s):  
El-Sayed Zanoun ◽  
Christoph Egbers ◽  
Ramis Örlü ◽  
Tommaso Fiorini ◽  
Gabriele Bellani ◽  
...  
Keyword(s):  
Reynolds Number ◽  
Energy Balance ◽  
Kinetic Energy ◽  
Experimental Evaluation ◽  
High Reynolds Number ◽  
Balance Equations ◽  
Pipe Flows ◽  
The Mean ◽  
High Reynolds

The Experimental Evaluation of the Performance of Multiphase Flow Meter: Effect of the Distance Between Two Meters

2009 ◽  
Author(s):  
Sang Hyun Park ◽  
Gerald L. Morrison
Keyword(s):  
Reynolds Number ◽  
Pressure Drop ◽  
Experimental Evaluation ◽  
Flow Coefficient ◽  
Base Line ◽  
Flow Conditions ◽  
Flow Meter ◽  
Flow Meters ◽  
Water Cut ◽  
Upstream Flow

In the previous studies of slotted flow meters, the repeatibility and reproducibility were studied under different flow conditions and different configurations. In accordance with these work, the present study examines the affects of the distance between the slotted plate. The preset 5D distance is expanded to the 10D. The flow coefficient, KY, the pressure drop, and the uncertainty analysis dependence upon this change is examined. There are definite changes in the results between the 5D distance and the 10D distance. As a base line, the flow coefficient, KY, showed 0.8% to 2% difference between the 5D and the 10D distance case. Depending upon the upstream flow conditions, the reproducibility of the slotted flow meter was affected. The pressure drop increased as the upstream Reynolds number increases. The result from the analysis of a water cut meter mounted downstream of a slotted flow meter showed that there are definitive relationships between the output of the water cut meter and the parameters of the flow.

The Molecular Transit Time and Its Correlation With the Stability of Externally Pressurized Gas-Lubricated Bearings

1963 ◽  
Vol 85 (2) ◽  
pp. 297-303 ◽  
Author(s):  
R. C. Turnblade
Keyword(s):  
Reynolds Number ◽  
Turbulent Flow ◽  
Transit Time ◽  
Experimental Evaluation ◽  
Theoretical Discussion ◽  
Basic Principles ◽  
Dimensionless Parameters ◽  
Gas Bearings ◽  
Fluid Mass ◽  
The Stability

This paper advances the hypothesis that the regimes of unstable operation of externally pressurized gas-lubricated bearings may be defined by certain dimensionless parameters in much the same way as the Reynolds’ number predicts the transition of laminar to turbulent flow. A theoretical discussion of the basic principles of gas bearings indicates that unstable operation is related to the capacity of a bearing to change its contained fluid mass. Some general expressions are developed which suggest the nature of some dimensionless parameters and permit experimental evaluation of the theory.

scholarly journals <i>Letter to the Editor</i>An analogy to the Reynolds number for the neutral gas component of a weak plasma

2001 ◽  
Vol 19 (1) ◽  
pp. 131-134
Author(s):  
C. M. Hall
Keyword(s):  
Reynolds Number ◽  
Electric Field ◽  
Electric Fields ◽  
Atmospheric Dynamics ◽  
Neutral Particles ◽  
Meteorology And Atmospheric Dynamics ◽  
Neutral Gas ◽  
Electric Fields And Currents ◽  
Induced Velocity ◽  
Gas Component

Abstract. The Reynolds number Re is used as a metric to assess whether or not a flow may contain turbulence. In a weakly ionised gas with an external electric field imposed, ions exert a drag on the neutral particles. Thus, a component of the neutral motion is attributable to the ion-drag. An analogy to Re has been proposed in which the ion-drag-induced velocity contribution to the neutral motion is used. This analogy thus represents the destabilising effect of the electric field on the neutral dynamics. Here quantisation of this proposed metric is investigated.Key words. Meteorology and atmospheric dynamics (turbulence) – Ionosphere (ionosphere-atmosphere interactions; electric fields and currents)

On swimming in a visco-elastic liquid

1979 ◽  
Vol 95 (1) ◽  
pp. 189-197 ◽  
Author(s):  
T. K. Chaudhury
Keyword(s):  
Reynolds Number ◽  
Phase Velocity ◽  
Elastic Property ◽  
Successive Approximation ◽  
Fluid Model ◽  
Second Order ◽  
Viscoelastic Liquid ◽  
Elastic Liquid ◽  
Induced Velocity

The velocity induced by a transversely waving infinite flexible sheet in a viscoelastic liquid is investigated by a method of successive approximation up to second order in the amplitude of oscillation of the sheet. The incompressible second-order fluid model has been used and it is found that the elastic property of the fluid augments self-propulsion (increases the induced velocity) in some range of Reynolds number (based on the phase velocity) and hampers it (reduces the induced velocity) in some other range with higher values of Reynolds number.

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