Viscosity Definition and 232 Threads

I saw an example where the work of a heart was found to be 2 watts based on the height of a person and the liters of blood that it pumped throughout the day. Since we have closed circulation systems (unless we have a cut, annerism, etc. ) I thought height would not matter, and in order to...

Hi.everybody How do I derive viscosity equation F=6π*r*μ?

guys i am doing fluid mechanics for the first time at university level the textbook that was recommended by the lecturer is crap and the study guide only refers to the textbook please guys need your help with this question 3 N is needed to push a 50 mm diameter piston, 30 mm long slides...

Hi all, This is my first post and my background is in Computer Science, so pardon me if my terminology is not correct or even I sound ignorant Physics-wise :) Anyways, I implemented a semi-Lagrangian based Navier-Stokes (NS) solver and it's running smoothly on a CUDA-capable GPU and I...

Homework Statement I'm going to be doing an experiment to determine the viscosity of golden syrup by dropping different size steel ball bearings into a jar of golden syrup and recording how long it takes for them to travel a certain distance when there at terminal velocity. so from the...

Drag at high Reynolds numbers is given by the formula: 0.5*\rho*V2*Cd*A Why does at the molecular (or at the micro) level the drag is independent of the viscosity?

We are performing an experiment to determine the viscosity of water using the falling sphere method. I understand that the ratio of the radius of the sphere to the radius of the container has to be within a certain range in order to avoid a false high viscosity value. And a correction factor is...

Can anyone tell me why this is true? I can't find an explanation anywhere, and it doesn't make sense to me geometrically either, especially for i=j. Isn't viscous force, by definition, a shear force? How can it produce a normal stress? Also why would Txy=Tyx? Why can't they be different...

Problem Statement A 50cm by 30cm by 20cm block weighing 150N is to be moved at a constant velocity of .8 m/s on an inclined surface with a friction coefficient of 0.27. (a) Determine the force f that needs to be applied in the horizontal direction. (b) if a .4mm thick oil film with a dynamic...

Homework Statement Does something like a viscosity constant of a cylinder exist? We are talking about an empty barrel rolling on a horisontal plane and the air friction. On the classes we got something like this c= 1.76h\cdot r where h is the barrel's height and r is the radius. How to find...

Hi, I'm performing some calculations and I need oil viscosity at 20°C. I have checked in some standards like SAE or ISO, but the lowest temperature I have found is 40°C. How may I extrapolate the viscosity a 20°C? Moreover I need a precise value of oil density, does someone know this value...

Hi, I am doing physics coursework on finding viscosity of fluids by dropping a marble into fluids, finding terminal velocity, then using stoke's law to find viscosity. (using density of fluid, sphere, sphere diameter etc). I have completed all the practical, now just the write up However ... I...

Homework Statement Help with the viscosity. The problem is in the attachment. My prof does not yet teach the lesson but we have to answer the problem. Homework Equations The Attempt at a Solution

hi all can someone explain me the units of Base oil viscosity of grease? for example is there a difference between grease rated at 200cSt and 200 mm2/s if so then what is the meaning of cSt and what does it stand for? thanks

I'm doing an essay for a Relativity course on the relativistic effects which would occur in daily life if the speed of light was somehow...lowered to a number such as 20m/s. My question is: "How would relativity affect motion though a liquid (such as swimming through a pool) at speeds such...

Homework Statement Two plane disks, each of radius 5cm, are mounted coaxially with their adjacent surfaces 1mm apart. They are in a chamber containing gas at STP (viscostiy of gas = 2.1 x 10^-5 Ns/m^2) and are free to rotate about the common acis. One of them rotates with angular velocity of...

if we use Poiseuille's equation, plotting the varying height of a water tank againts the rate of flow, does the gradient of the graph tell us the viscosity, or do we re-arrange the equation to find viscoisty. Thanks

Homework Statement A flat circular disc of radius 1.0m is rotated at an angular velocity of 0.65 rad/sec over a fixed flat surface. An oil film separates the disk and the surface. If the viscosity of the oil is 16 times that of water (20 degree C) and the space between the disk and the fixed...

Homework Statement A patient is to be given a blood transfusion through a tube from a raised bottle to a needle inserted in a vein. The needle has an inner diameter of 0.5mm and is 4.0cm long. If the required blood flow rate is 4.0cm^3/minute, how high should the bottle be placed above the...

The question is attatched. The question is number 8. I simply do not understand, if the question is right at all, because I believe that options A and D are both correct. But, B it seems is the answer. High temp means low visc. and vice versa, leading to A and D being correct. Please...

Does the viscosity of air change with change in the degree of humidity at room temperature?

Calculating the viscosity of a 'test fluid' HELPPPPPPP! Can anyone please help me calculate the viscosity of each of the test fluids below. there are 5 of them and have each been tested 6 times. I am supposed to be doing straight line graphs and using the gradient to use to calculate the...

I have been doing a bit of research on building a low temperature Stirling engine, and I came across this website, http://heetgasmodelbouw.ridders.nu/Webpaginas/pagina_koffiekop_jan/koffiejan_frameset.htm The design on this website looks nice, and I would like to give it a go (after I build a...

In a question,I found a unit call 'viscosity',but i don't what it is can anyone explain the definition,I have no idea of this completely,THX

Hello all, I'm trying to nail down why the viscosity of air helps it bend around a curve. I have a specific, simplified example in mind to cut away other phenomena. Imagine the region immediately behind the camber of the top of a typical airfoil. That is, the place where the slope of the...

Hi everibody... I do not know is this question will be stupid... is there relation mathematical, phisics,etc..between wet ability and viscosity of one liquid type oil? Tanks and best regard

Homework Statement Hey, I am doing some work with torricellis equation and I have some questions. I am using the equation: dH/dt*A(h)=-B*squareroot(2*g*h) My question is, in my textbook it says the general formula is: dH/dt*A(h)=-0.6*B*squareroot(2*g*h) I want to know where the...

Fluids have viscosity, but do gasses have it? And in that case, what is the viscosity for normal air (I know air isn't one gas)?

How does the viscosity of a fluid in a circular can affect the way the can rolls? For example, 2 cans of similar size, volume, and mass are rolled down a ramp with the same slope. The can with a viscous liquid will take more force to begin rolling than a can with a less viscous liquid, but once...

How does the viscosity of a fluid in a circular can affect the way the can rolls? For example, 2 cans of similar size, volumn, and mass are rolled down a ramp with the same slope. The can with a viscous liquid will take more force to begin rolling than a can with a less viscous liquid, but once...

Hi, I'm looking for a little bit of help in this matter, I'm trying to put up a general formula of the internal force/volume in a fluid in a spot, as a function of how the velocity varies locally around that spot. What I started with was a formula I found in a book called "Physics Handbook...

An object rests on a high viscosity liquid like jelly what properties of the liquid keep it from breaking the surface of the jelly and sinking. (object deforms surface but doesn't break it) is it surface tension? Viscosity? How would the load carrying capacity of the jelly be tested?

I was just wondering. Say you have two different liquid with two different viscosities (water and oil, etc). If you have them in two different containers, and having the same amount in each container, say 500 mL. You heat them both to some temperature, say 100 F. Since liquid expands when it is...

Is there an equation that relates viscosity of water to temperature? If not, is there a reliable table somewhere on the internet? I'm searching for the viscosity at 20°C ± 3°C.

Since there are no frictional forces acting on the superfluid my intuition would tell me that there is no way for the liquid to "climb" the sides of a container. Obviously though, intuition isn't the best thing to go by when it comes to superfluids. I'm just wondering: what mechanism drives it...

hi, this is the first time i learn about viscosity, but I don't know where to start with this question: At 18.5°C, the viscosity of 1 wt% aqueous sugar solution is 1.025 times higher than the viscosity of pure water. At the same temperature, the diffusion coefficient of the sugar molecules is...

Any hints on how to derive the glass viscosity? n=n(0)exp(Q/RT)?

Hi, even though this is my first post, Physics Forums have helped my a over that past couple of years. Just searching old PF threads usually gave me the answer I was looking for. So thanks. I am currently doing Advanced Higher (Scottish Qualification) Physics Investigation on Viscosity. During...

What are the factors that affect viscosity of incompressible Newtonian fluid? Here is what I think: Temperature: When we increase the temperature of a fluid (controlled volume) the frequency ofintermoleculer collisions increases. Does this mean viscosity decreases? And if so, does...

Homework Statement Find the viscosity of water given that; flow rate (cm^3 s^{-1}) = 2.0 height from tube (m) = 0.1 l (m) = 0.2 r (mm) = 1 \rho = 1000 g = 9.81 Using the equations; x = \frac{Flow Rate}{Height} x = \frac{\pi \rho gr^4}{8l\eta}The Attempt at a Solution Okay so first, and...

I've managed to calculate the viscosity of glycerol to be about 1.9 P. Google says it's supposed to be 1.5. Could I say that evaporated water has caused the glycerol to become more viscous than it should be? (It could just be a thicker glycerol but I'm just looking things to blab on about)...

I'm trying to find the viscosity of some glycerol that we dropped various steel balls down using the equation: V = [2r^2 (p – σ) g] / 9η I put in these values: p = 7800 kg m-3 σ = 1200 kg m-3 g = 9.8 m s-2 And ended up with the equation. η = 129360r^2 / 9V My problem is that I...

Homework Statement The change of viscosity with temperature can be described using the general equation ln(µ) = A + (B/T), where µ represents dynamic viscosity, T represents temperature (Kelvin), and A and B are constants. a) Find the values of A and B for raw milk, using the viscosity...

How to calculate the dynamic viscosity of air at high alttitudes,i want to calculate it at hight 4000m abovesea level at that hight the temp. is 262 kelven degrees. Any thoughts?

finally in my search to understand why the boundary layer separates from the surface of a baseball I have come to understand that the reasons for the separation of the boundary layer from a baseball is incredibly similar to the separation of the boundary layer from a wing of an airplane after...

a question on boundary layers viscosity and air seperating from a ball I have a few questions that have to do with a viscosity on the surface of an object, the boundary layer and the boundary layer separating from the surface of a baseball! 1) my first question is if we had a stationary...

1. Homework Statement where: l = the length of the tube in cm r = the radius of the tube in cm p = the difference in pressure of the two ends of the tube in dynes per cm2 c = the coefficient of Viscosity in poises (dyne-seconds per cm2) v = volume in cm3 per second pi =...

Hi all. I am learning things about incompressible turbulent mena flow. I am completely confused by these terms: moleculr viscosity and eddy viscosity. What are they? Is molecular viscosity the same as the visocosity of the fluid we often use? And what exactly is eddy viscosity? I know it is...

Homework Statement A flat plate viscometer consists of a disc of diameter 50mm rotating at 300rpm in close proximity to a fixed horizontal plate. When the gap between the plates is 0.1mm, it is found that the torque required to drive the disc is 0.2Nm. What is the viscosity of the liquid...

Hi guys, For a prac we did, we are given the properties of a particular oil. Density (kg/m^3) = 876 Viscosity (Ns/m^2) = 20.0x10^(-3) I believe it is the dynamic viscosity. Now is this viscosity correct? Or should it be 2.0x10^(-3)