scholarly journals Linking the Unsteady Force Generation to Vorticity for a Translating and Rotating Cylinder

2019 ◽  
Author(s):  
Pascal Gehlert ◽  
Holger Babinsky
Keyword(s):  
Rotating Cylinder ◽  
Force Generation ◽  
Unsteady Force

Numerical Study on the Unsteady-Force-Generation Mechanism of Insect Flapping Motion

AIAA Journal ◽  
2008 ◽  
Vol 46 (7) ◽  
pp. 1835-1848 ◽  
Author(s):  
Jung-Sang Lee ◽  
Jin-Ho Kim ◽  
Chongam Kim
Keyword(s):  
Numerical Study ◽  
Generation Mechanism ◽  
Force Generation ◽  
Flapping Motion ◽  
Unsteady Force

Transient force augmentation due to counter-rotating vortex ring pairs

2015 ◽  
Vol 785 ◽  
pp. 324-348 ◽  
Author(s):  
Zhidong Fu ◽  
Hong Liu
Keyword(s):  
Vortex Ring ◽  
Force Generation ◽  
Vortex Rings ◽  
Force Coefficient ◽  
Piston Cylinder ◽  
Unsteady Force ◽  
New Perspective ◽  
Spatial Locations ◽  
Ring Interaction ◽  
Transient Force

Of particular significance to biological locomotion is vortex ring interaction. In the wakes of animals, this unsteady process determines the changes in the impulse of counter-rotating vortex ring pairs (VRPs), which consist of two vortex rings with opposite sense of rotation. In this paper, these VRPs are proposed to be of particular importance to unsteady force generation. We carry out numerical computations, simulating the piston–cylinder apparatus, to study the transient changes in the impulse of counter-rotating VRPs composed of a positive and a negative vortex ring. We model the negative vortex ring (NeVR) of a VRP by making reasonable assumptions about their vorticity distributions and spatial locations, which are initially prescribed. The result of modelling is superimposed on the flow, which has a pre-existing positive vortex ring (PoVR), leading to a VRP. The simulation quantitatively demonstrates that the unsteady force resulting from a VRP is significantly larger compared with an isolated PoVR (without an NeVR). The force enhancement is also correlated to vortex configurations. A normalised force coefficient characterising force augmentation over the entire stroke is given. The force augmentation coefficient grows significantly and then reaches a plateau as the momentum input increases. The results are consistent with those in fully unsteady vortex interaction, which involves the generation of an NeVR. It is suggested that counter-rotating VRPs could offer a new perspective to explain unconventional force generation for biological swimming and flying.

Lack of myostatin in mice results in excessive muscle but impaired force generation, tubular aggregates and alterations in fibre type profile

2005 ◽  
Vol 36 (02) ◽  
Author(s):  
H Amthor ◽  
R Navarette ◽  
SC Brown ◽  
R Macharia ◽  
F Muntoni ◽  
...  
Keyword(s):  
Fibre Type ◽  
Force Generation ◽  
Tubular Aggregates

Some Consequences of Coulomb Friction in Modeling Longitudinal Traction

1990 ◽  
Vol 18 (1) ◽  
pp. 13-65 ◽  
Author(s):  
W. W. Klingbeil ◽  
H. W. H. Witt
Keyword(s):  
Shear Force ◽  
Coulomb Friction ◽  
Interfacial Shear ◽  
Force Generation ◽  
Behavior Patterns ◽  
Inflation Pressure ◽  
Friction Law ◽  
The Coefficient Of Friction ◽  
Coulomb Friction Law ◽  
Perfect Adhesion

Abstract A three-component model for a belted radial tire, previously developed by the authors for free rolling without slip, is generalized to include longitudinal forces and deformations associated with driving and braking. Surface tractions at the tire-road interface are governed by a Coulomb friction law in which the coefficient of friction is assumed to be constant. After a brief review of the model, the mechanism of interfacial shear force generation is delineated and explored under traction with perfect adhesion. Addition of the friction law then leads to the inception of slide zones, which propagate through the footprint with increasing severity of maneuvers. Different behavior patterns under driving and braking are emphasized, with comparisons being given of sliding displacements, sliding velocities, and frictional work at the tire-road interface. As a further application of the model, the effect of friction coefficient and of test variables such as load, deflection, and inflation pressure on braking stiffness are computed and compared to analogous predictions on the braking spring rate.

Viscosity Evaluation of Multi-phases Flux by Rotating Cylinder Method

2009 ◽  
Vol 95 (12) ◽  
pp. 807-812 ◽  
Author(s):  
Sohei Sukenaga ◽  
Shinichiro Haruki ◽  
Yoshinori Yamaoka ◽  
Noritaka Saito ◽  
Kunihiko Nakashima
Keyword(s):  
Rotating Cylinder ◽  
Cylinder Method

Israel’s Ground Forces in the Occupied Territories

2020 ◽  
Vol 35 (2) ◽  
pp. 37-57
Author(s):  
Eyal Ben-Ari ◽  
Uzi Ben-Shalom
Keyword(s):  
High Intensity ◽  
Force Generation ◽  
Institutional Autonomy ◽  
Multiple Forms ◽  
The West ◽  
Occupied Territories ◽  
Media Monitoring ◽  
Israel Defense Forces ◽  
And Control ◽  
Over Time

The Israel Defense Forces (IDF) routinely rotate ground forces in and out of the Occupied Territories in the West Bank. While these troops are trained for soldiering in high-intensity wars, in the Territories they have long had to carry out a variety of policing activities. These activities often exist in tension with their soldierly training and ethos, both of which center on violent encounters. IDF ground forces have adapted to this situation by maintaining a hierarchy of ‘logics of action’, in which handling potentially hostile encounters takes precedence over other forms of policing. Over time, this hierarchy has been adapted to the changed nature of contemporary conflict, in which soldiering is increasingly exposed to multiple forms of media, monitoring, and juridification. To maintain its public legitimacy and institutional autonomy, the IDF has had to adapt to the changes imposed on it by creating multiple mechanisms of force generation and control of soldierly action.

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