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  • 1
    Electronic Resource
    Electronic Resource
    Geometric optimisation of a micromachine with a spiral tail immersed in viscous medium (1997)
    Springer
    Computational mechanics 20 (1997), S. 267-271 
    Details
    ISSN: 1432-0924
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract A model of micromachine with a spiral tail moving in a highly viscous fluid has been simulated using the Boundary Element Method. The trajectory of this micromachine is a straight line and it swims with a velocity close to that of a microorganism with a helical tail. An optimisation process has been carried out in order to find the optimal parameters to obtain the highest translational velocity. The optimum capsule-shaped head of this micromachine has an aspect ratio of about 0.5; the length of the tail is about 8 times the radius of the head, about 4.2 times of its width, and consists of 1.5 wavelengths. The dimensional proportions obtained here are in excellent agreement with previous studies on the motion of microorganisms with helical tails.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004660050247
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Hydrodynamic interaction between two nearby swimming micromachines (1997)
    Springer
    Computational mechanics 20 (1997), S. 551-559 
    Details
    ISSN: 1432-0924
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Numerical results for two nearby swimming micromachines, obtained by the boundary element method (BEM), are reported in this paper. Two neighbouring configurations, side by side and in tandem, are considered and the translational and rotational velocities together with the force exerted on the micromachines are given. It is demonstrated that, for both configurations, the approximate reflection method gives comparable results to the full solutions. In the side by side configuration, hydrodynamic interaction is significant when the separation distance is less than about 1.5 of the total length of the machine. A propulsion advantage in the tandem configuration is found, where the leading machine acquires a higher velocity and the results obtained by the reflection method agree well with the full BEM solution.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004660050275
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    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Lubrication approximation in completed double layer boundary element method (2000)
    Springer
    Computational mechanics 26 (2000), S. 388-397 
    Details
    ISSN: 1432-0924
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract This paper reports on the results of the numerical simulation of the motion of solid spherical particles in shear Stokes flows. Using the completed double layer boundary element method (CDLBEM) via distributed computing under Parallel Virtual Machine (PVM), the effective viscosity of suspension has been calculated for a finite number of spheres in a cubic array, or in a random configuration. In the simulation presented here, the short range interactions via lubrication forces are also taken into account, via the range completer in the formulation, whenever the gap between two neighbouring particles is closer than a critical gap. The results for particles in a simple cubic array agree with the results of Nunan and Keller (1984) and Stoksian Dynamics of Brady et al. (1988). To evaluate the lubrication forces between particles in a random configuration, a critical gap of 0.2 of particle's radius is suggested and the results are tested against the experimental data of Thomas (1965) and empirical equation of Krieger-Dougherty (Krieger, 1972). Finally, the quasi-steady trajectories are obtained for time-varying configuration of 125 particles.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004660000188
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    Paper (German National Licenses)
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  • 4
    Electronic Resource
    Electronic Resource
    On the path and efficiency of two micromachines with rigid tails (1996)
    Springer
    Computational mechanics 18 (1996), S. 192-199 
    Details
    ISSN: 1432-0924
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract  This paper reports on the results of investigation of the swimming of two different micro-machines. Mechanically each of these micro-machines consists of a head (containing an electromechanical power source) and a tail which moves relative to the head as a rigid body. The problem is approached theoretically by considering the types of movement which can occur for these micro-machines immersed in a viscous medium. The first micro-machine has a tail which oscillates in vertical plane, therefore the trajectory of this machine is in that plane too. The tail of the second micro-machine rotates conically, so it produces a three dimensional helical path in space with its axis approximately along the direction of tail centreline. Using the boundary element method for solving the traction equations on the surface of the tail, and a time-dependent Euler kinematic scheme to plot the path, the net propulsive force and torque, the translational velocity, angular velocity and the trajectory of each machine are calculated. Evaluation of the path and the direction of motion for each micro-machine using different dimensional parameters can give an idea of the efficiency for such machines with rigid tails.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00369937
    Library Location Call Number Volume/Issue/Year Availability
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    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Modelling micromachines with elastic parts in a viscous environment (1997)
    Springer
    Computational mechanics 20 (1997), S. 242-246 
    Details
    ISSN: 1432-0924
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract  Designing micromachines with elastic components has not been addressed by the research community. In this paper, the Boundary Element Method for Stokes flows is used to model a micromachine consisting of a “head” and an elastic “tail” immersing in viscous fluid. The general numerical implementation can be used for a wide range of micromachines with rotating and arbitrarily deforming tail. A particular periodic tail motion is suggested for illustrative purposes. To assist the forward motion, enlarging of the head during the second half cycle only is proposed. A physical model has been suggested that may be used for comparing its performance with that deduced from our calculations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004660050244
    Library Location Call Number Volume/Issue/Year Availability
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    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    On the path and efficiency of two micromachines with rigid tails (1996)
    Springer
    Computational mechanics 18 (1996), S. 192-199 
    Details
    ISSN: 1432-0924
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract This paper reports on the results of investigation of the swimming of two different micro-machines. Mechanically each of these micro-machines consists of a head (containing an electromechanical power source) and a tail which moves relative to the head as a rigid body. The problem is approached theoretically by considering the types of movement which can occur for these micro-machines immersed in a viscous medium. The first micro-machine has a tail which oscillates in vertical plane, therefore the trajectory of this machine is in that plane too. The tail of the second micro-machine roates conically, so it produces a three dimensional helical path in space with its axis approximately along the direction of tail centreline. Using the boundary element method for solving the traction equations on the surface of the tail, and a time-dependent Euler kinematic scheme to plot the path, the net propulsive force and torque, the translational velocity, angular velocity and the trajectory of each machine are calculated. Evaluation of the path and the direction of motion for each micro-machine using different dimensional parameters can give an idea of the efficiency for such machines with rigid tails.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00369937
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
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