The drag on a cloud of spherical particles in low Reynolds number flow

1969 ◽  
Vol 38 (3) ◽  
pp. 537-546 ◽  
Author(s):  
Christopher K. W. Tam

A formula for the drag exerted on a cloud of spherical particles of a given particle size distribution in low Reynolds number flow is derived. It is found that the drag experienced by a particle depends only on the first three moments of the distribution function. A treatment of viscous interaction betweenNparticles to the lowest order is carried out systematically. By appealing to the concept of ‘randomness’ of the particle cloud, equations describing the averaged properties of the fluid motion are derived. The averages are formed over a statistical ensemble of particle configurations. These mean flow equations so obtained are in a form resembling a generalized version of Darcy's empirical equation for the motion of fluid in a porous medium. The physical meaning of these equations is discussed.

AIAA Journal ◽  
1972 ◽  
Vol 10 (10) ◽  
pp. 1381-1382
Author(s):  
CLARENCE W. KITCHENS ◽  
CLARENCE C. BUSH

2010 ◽  
Vol 39 (9) ◽  
pp. 1529-1541 ◽  
Author(s):  
Shengyi Wang ◽  
Derek B. Ingham ◽  
Lin Ma ◽  
Mohamed Pourkashanian ◽  
Zhi Tao

Robotica ◽  
2021 ◽  
pp. 1-17
Author(s):  
Hossein Nejat Pishkenari ◽  
Matin Mohebalhojeh

Abstract Microrobots with their promising applications are attracting a lot of attention currently. A microrobot with a triangular mechanism was previously proposed by scientists to overcome the motion limitations in a low-Reynolds number flow; however, the control of this swimmer for performing desired manoeuvres has not been studied yet. Here, we have proposed some strategies for controlling its position. Considering the constraints on arm lengths, we proposed an optimal controller based on quadratic programming. The simulation results demonstrate that the proposed optimal controller can steer the microrobot along the desired trajectory as well as minimize fluctuations of the actuators length.


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