The viscosity of a fluid is a measure of its resistance to flow, or be deformed, stirred, and changed shape.
Questions tagged [viscosity]
561 questions
13
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1 answer
Dive into a pool of mayonnaise. What happens next?
First, some train of thought to show I am not completely insane.
Last night there was a college football bowl game, the Duke's Mayo Bowl. I naturally assumed the winner would receive a lifetime supply of mayonnaise.
Then I thought, what would one…
Jason P Sallinger
- 1,305
3
votes
2 answers
Viscosity forces and Depth of water
I was wondering if the viscosity force depends on the depth of water.
I mean it is much more harder to swim in the ocean at a depth of 1km than swimming at the surface due to the viscosity forces ?
Smilia
- 165
2
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1 answer
Would a fluid with zero viscosity reach an equilibrium
My hunch is yes, but I can't think how to prove it.
An argument against this is you have a box with a divider in the middle, one side is filled up higher than the other. The divider is removed, you will get waves in the fluid, when the viscosity is…
DanOc004
- 53
2
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1 answer
Velocity in a viscous fluid
The force $F$ to carry a plate of area $A$ with velocity $v$ in a fluid of depth $d$ is given by
$$\frac{F}{A}=\eta\frac{v}{d}.$$
Hence if the depth is $kd$, the force becomes $F/k$.
Do this relations hold for a ship in water?
user7669
- 153
2
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0 answers
Chapman-Enskog theory for diatomic gas
I have rarefied, dilute, diatomic gas (oxygen) and I have to calculate the viscosity using the Chapman-Enskog theory; however I couldn't find anywhere the formula the allows me to do such calculation. The only formula I was able to use is the one…
Federico Gentile
- 251
2
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1 answer
Say, a liquid is made to flow in a tube. Why does the layers of the liquid in contact with walls of the pipe have zero velocity?
Say, a liquid like water is made to flow in a pipe. Why does the layer of water near the walls of the pipe have zero velocity? Does that mean that the layer of water near the pipe is stationary and the other layers are in motion? How is that even…
siddhu99
- 23
1
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3 answers
Why doesn't the object slow down more after attaining the terminal velocity in liquid?
When an object falls down in a liquid it has two forces working on it one gravity and another is viscous drag . Now when these forces are same the object attains the terminal velocity in liquid. Now if these forces have been neutralized then why…
Nobody recognizeable
- 1,139
1
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1 answer
Intrinsic Viscosity
I'm presently undergoing an Experiment for the determination of the viscosity of Ficoll-70 using Ostwald viscometer to calculate the time and a digital weighing balance to determine the weight of a specified volume of the solution at different…
stp30
- 387
0
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0 answers
Viscosity of fluids near the surface
is the viscosity of a fluid maximum at the layers adjacent to the surface?
I think this because the molecules of liquid now experience a greater friction force because the adhesive forces also resist their ability to flow.
Spluesh
- 61
0
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1 answer
Application of Newton's law of viscosity in a problem on disc viscometer
Hi ,
My instructor solved this problem using a circular elemental strip of thickness 'dr'. He told me we get only shear stress in horizontal layers of fluid. He used Newton's law of viscosity to get the value of shear stress at top face of plate.…
Harii Pavan
- 55
0
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1 answer
Why is viscous force directly proportional to velocity gradient
My textbook says that viscous force is directly proportional to the velocity gradient (du/dz). But I am finding this a bit against my logic. What I understand is that viscous force tries to resist the laminar flow of a fluid. My textbook also…
Krish Vasa
- 113
0
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1 answer
Dynamic or Kinematic viscosity
Utilising the formula $\eta = \frac { \left( 2\left( { p }_{ s }-{ p }_{ l } \right) g{ r }^{ 2 } \right) }{ 9v } $
Where $p_s$ is density of a sphere with radius $r$ traveling at velocity $v$ through a liquid $l$.
I would like to know whether this…
Riccardo Perego
- 101
0
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1 answer
A viscous liquid moving from different holes
Say, we have bottled viscous liquid - such as a dishwashing liquid. There are two different caps for the bottle. One with a smaller hole, one with slightly bigger hole. Both holes are very small though.
Now, we invert the bottle with cap 1 on…
Curious
- 1
0
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1 answer
Derivation of Maxwell viscoelastic material stress
I have a problem with understanding of derivation of stress equation $\sigma(t)$ for Maxwell rheological model. Below is the classic equation:
$$\dot{\sigma}(t) + \sigma(t) \, \frac{E_0}{\eta}=E_0
\,\dot{\varepsilon}(t) \tag{1}$$
which is a…
Adalbert
- 15
0
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1 answer
Where does this viscosity formula come from?
I was reading a scientific article and i came across this formula:
$$\frac{\tau_{xy}}{V_{/x}} = \eta_{0}+\eta_{2}V_{/x}^{2}+\eta_{4}V_{/x}^{4} $$
which refers to the calculation of the viscosity of oxygen; $\tau_{xy}$ is the stress tensor and…
Federico Gentile
- 251