Über die innere Reibung zäher Flüssigkeiten und ihre Abhängigkeit vom Druck

Ladenburg, Rudolf

doi:10.1002/andp.19073270206

Cited by 64 publications

(6 citation statements)

References 16 publications

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“…and Kraemer (54) and Friedman (52,53) in connection with their experiments on the diffusion of nonelectrolytes through gelatin gels. These authors point out the ap plicability to restricted diffusion of the Ladenburg-Faxen correction (45, 81,82) of Stokes Law in systems where the particle size is comparable with the dimensions of the sedimentation chamber. For the case of spherical particles of radius (a>, sedimenting (diffusing) in cylindrical vessels of radius r, this correction takes the form:…”

Section: Dt@sion Of Solandes Through Membnmesmentioning

confidence: 99%

Passage of Molecules Through Capillary Walls

Pappenheimer¹

1953

Physiological Reviews

882

265

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Section: Dt@sion Of Solandes Through Membnmesmentioning

confidence: 99%

Passage of Molecules Through Capillary Walls

Pappenheimer¹

1953

Physiological Reviews

882

265

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“…where R is the radius of the container and h its height [16,17] If the condition Re<1 is not fulfilled, it is not expected that the Stokes' law will be valid. Also, when a sphere moves inside a viscous fluid, turbulent flow usually arises for Re¬10 3 .…”

Section: Theoretical Considerationsmentioning

confidence: 99%

A non-traditional fluid problem: transition between theoretical models from Stokes’ to turbulent flow

et al. 2018

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In the context of fluid mechanics courses, it is customary to consider the problem of a sphere falling under the action of gravity inside a viscous fluid. Under suitable assumptions, this phenomenon can be modelled using Stokes’ law and is routinely reproduced in teaching laboratories to determine terminal velocities and fluid viscosities. In many cases, however, the measured physical quantities show important deviations with respect to the predictions deduced from the simple Stokes’ model, and the causes of these apparent ‘anomalies’ (for example, whether the flow is laminar or turbulent) are seldom discussed in the classroom. On the other hand, there are various variable-mass problems that students tackle during elementary mechanics courses and which are discussed in many textbooks. In this work, we combine both kinds of problems and analyse—both theoretically and experimentally—the evolution of a system composed of a sphere pulled by a chain of variable length inside a tube filled with water. We investigate the effects of different forces acting on the system such as weight, buoyancy, viscous friction and drag force. By means of a sequence of mathematical models of increasing complexity, we obtain a progressive fit that accounts for the experimental data. The contrast between the various models exposes the strengths and weaknessess of each one. The proposed experience can be useful for integrating concepts of elementary mechanics and fluids, and is suitable as laboratory practice, stressing the importance of the experimental validation of theoretical models and showing the model-building processes in a didactic framework.

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“…The steady-state velocity of a solid sphere falling in an undisturbed, infinite fluid medium at Reynolds number less than about 2 is given by Stokes' law: gD'Kp» -p) 18m (1) For the instantaneous velocity as a function of the vertical distance traversed by the sphere, Ladenburg (5) Hunter (4), from experiments with fluids having viscosities of 4 poises (glycerol) and 700 poises (glucose), recommended division by the following for the wall correction:…”

Section: Analyticalmentioning

confidence: 99%