viscous Definition and 108 Threads

For a situation where we have two infinite flat parallel plates with a viscous fluid in between if the upper plate if acted upon by a constant force then the plate should accelerate. The fluid layer adjacently below the upper plate should have the same acceleration as this plate (due to no-slip...

I am trying to find an expression for viscous dissipation for burger's vortex Velocity field which only has velocity component in the V theta direction. I'm confused as to which equation for viscosity dissipation is correct. I am seeing a lot of different things tau:S, tau:delV..which one is...

what's the relation of the viscous hydrodynamic forces and swirl？

Are the viscous hydrodynamic forces and the nonlinear viscous hydrodynamic forces applied on offshore platform in the ocean？ The platform is fixed.

The viscous hydrodynamic forces will increase with increase of the velocity of ship？ Can the viscous hydrodynamic forces be neglected if the velocity of ship is small　？

Homework Statement The system can pivot at point O and I am taking small angle approximations. I am trying to determine the Lagrangian, ##\mathcal{L} = T - U## for the following system: Homework Equations E-L equation with dissipation: ##\frac{\partial\mathcal{L}}{\partial q_i} -...

Homework Statement A viscously damped system has a stiffness of 5000 N/m, critical damping constant of 0.2 N-s/m, and a logarithmic decrement of 2.0. If the system is given an initial velocity of 1 m/s, determine the maximum displacement. Homework EquationsThe Attempt at a Solution From the...

I have some data from an electric motor found here: http://www.engelantriebe.de/pdf/DAT_HLR26_11-13_engl.pdf However, it does not include information about the coefficient of torsional viscous damping which I need for a Simulink model. The units for torsional viscous damping are Nm.s/rad...

Hi Forum. So I'm doing a physics experiment where I drop marbles in different viscous liquids and I am suppose to discuss the relationship of the marble's velocity. But I am changing the marble's diameter and mass at the same time since I don't have any marbles which have the same mass but...

Homework Statement A fluid of viscosity \nu is rotating with uniform angular velocity \Omega inside a cylinder of radius a that is also rotating. At time t = 0, the cylinder is brought to a rest. The circular motion of the fluid is gradually slowed down due to the viscosity; show that u_\theta...

I am designing a test rig for my company to test seals. What i have is a shaft spinning in a fluid column that is pressurized to 30 bar. The shaft is spun by a motor and i am currently trying to figure out what motor i should select. The fluid is a C4 SAE 30 Oil, quite viscous actually. My...

hey pf! in reading a book on viscous stresses i found the following: \tau_{ij}=2\mu\Big(s_{ij}-\frac{1}{3}s_{kk}\delta_{ij}\Big) where einstein summation is used. now we have s_{ij}=\frac{1}{2}\Big(\frac{\partial u_i}{\partial x_j}+\frac{\partial u_j}{\partial x_i}\Big) and then the claim is...

Hi, I'm trying to solve the flow profile inside an inhomogeneous porous material between two parallel moving plates (essentially Couette flow with a deviation), and I model my system by the following equations: \nabla^2 \mathbf{u} = p(x,y,z) \mathbf{u}\\ \nabla \cdot \mathbf{u} = 0...

How exactly do you derive it without using tensors? You use Newton's frictional law on a 3d block of fluid, instead of just on fluid surfaces, but I can't 100% visualize how. So is there any simple derivation, or at least explanation? \mu \nabla ^2 \vec{V}

In work that I've been doing, we've come across an interesting problem. In a manufacturing process, a highly viscous, non-Newtonian fluid goes down a vertical chute and then gets pushed horizontally out the bottom by some rotating screws. Sometimes, the fluid gets pushed out the bottom, but...

Hello, First post hear so bear with me. I have a mass in free fall with a viscous friction which can be derived from the dissipative potential Kv2/2. I must find the Lagrangian and proove that the maximum speed is v=mg/K. I have the following Lagrangian...

Hey guys I'm putting together a lightweight bulletproof armour and need a non reactive viscous gel to be placed in it. It cannot be flammable as hot shards of metal will be in contact with it and it needs to be relatively viscous to keep some loose parts from moving around to much. Can anybody...

Homework Statement I am currently looking for a (simplified) model to see how far/fast a object will sink in a high viscous fluid. I found a lot of information about sinking spheres and the maximum contact angle with the fuild because of the surface tension before it sinks. And a example...

Homework Statement I have the statement, variables and given/known data in the picture along with relevant equations and solution attempt. Homework Equations The Attempt at a Solution I think I did the first part right. But I'm unsure about part B. The distance between the...

Homework Statement That is the problem statement. I can't seem to get started on part a. For part b I can find the velocity profile of the viscous liquid form the equations of motion relating velocity and change in pressure, find the avg velocity, and find the change in pressure from...

Everytime I see a picture of the large scale structure of space with matter arranged in a web like form, I come to think of the fenomenon of viscous fingering in fluids between to surfaces when they are moved apart. Since space is expanding as well, maybee these structures have something to do...

Homework Statement Hi, my first post here! I have a Thermodynamics resit over the summer and I'm trying to get my head around viscous flow, I'm stuck at a question and need help! Thanks :) Glycerine discharges to the atmosphere through a circular pipe 100mm in diameter. The gauge pressure 50m...

A sphere inside an elevator is falling at terminal velocity. Say the elevator cables break and it starts to freefall, what happens to the sphere's velocity? I have developed some rudimentary solution but would like to see a confirmation.

I'd expect that since they carry more kinetic energy, they are more fluid. Thanks!

Hello, I understand the tangential shear stresses (or forces) acting on a fluid element due to friction between moving fluid layers, but I can't imagine how viscosity might cause a normal force (on a fluid element)...explain please!

Hello, I have the following system (see enclosed figure): A viscous (non Newtonian) fluid at high temperature is going trough a tube at a known mass flow, at the exit there is an inclined plane at a given angle (b). I would like to estimate in some way how the inclined plane at the exit...

Homework Statement In an experiment to determine the viscosity of some oil, a ball is dropped into some oil. The position of the ball is given by the formula y=Y+At+Be-Ct. At t=0, y=0.070 m, the velocity dy/dt is 0 and the acceleration is 0.0983 m/s2. As t→∞ the velocity approaches 0.480 m/s...

Hello, I'm looking at this problem which states: "A parallel air flow along a semi infinite flat plate has undisturbed parameters as follows: " Then they list the speed, temprature, viscousity and pressure. "Demonstrate that the boundary layer can treated by means of incompressible...

A Newtonian fluid is a continuous medium with viscosity and can "stick to itself". An ideal gas is a collection of non interacting point particles. Obviously at equilibrium, air can be treated as an ideal gas, while dynamically it is treated as a Newtonian fluid. But it cannot be both (since...

Homework Statement A ball falls from rest through a viscous fluid in a tall beaker of height H. It reaches terminal velocity at height H/2. Draw the energy-time graph for kinetic energy and gravitational potential energy on the same axes. Homework Equations F=6πηrv The Attempt at a...

I guess the Earth's surface pulls around the lower atmosphere with viscous drag effects? What about the upper atmosphere? Does it rotate with a slower absolute tangential velocity? If so, is there any pressure difference that caused by the difference in velocities that would cause any...

Hi. may i ask the relationship(formula) between frequency and viscous friction in a spring?

hi.. may i ask what is the relationship(formula) between the viscous friction and the frequency? if i know the value of k(spring constant), M(mass), and f(frequency), am i able to find out friction coefficient, b?

I'm dropping a sphere from a known height, and it enters a viscous fluid. I know the initial velocity as it enters the fluid, from there I need the velocity as it falls through the fluid (as a function of time). I know it should approach it's settling velocity (terminal velocity) and from...

I've been doing some research on sphere aerodynamics, in particular that of soccer balls, and was wondering if there was any way to separately calculate the pressure / form drag, and also the surface / viscous / skin drag. I know that Stoke's Law of F=6(pi)RnVc, where R is the radius of the...

Homework Statement I have a cylinder of radius R translating (in radial direction) with velocity U in a viscous fluid at Re<<1. Find the force exerted on the cylinder per unit lengthHomework Equations Re<<1 so the Navier-Stokes equation simplifies to the Stokes equation: \nabla P=\mu \nabla^2 v...

Homework Statement Droplets in a deodorant spray have mass of about (4x10^-12) kg and a radius of about 0.1mm. Estimate the terminal velocity of the droplets in Air of Viscosity (2x10^-5)Nsm^-2. Homework Equations Stoke's Law, F = 6pi rvu where r = radius, v = velocity and u = viscosity...

When a sphere radius r has a velocity v in a liquid .It will has a drag force exerted on the sphere. The drag force is equal to 6\pi\etarv (Stoke's law) where \eta is the fluid's dynamic viscosity Where the drag force comes from ? How does this force occur?

Homework Statement I am working with a problem of damped harmonic motion. I am given that the motion is in a medium that exerts a force of 2N when the speed is 4 cm/s. The mass is 5kg. Homework Equations C = F/v The Attempt at a Solution I thought that the viscous damping...

Homework Statement Which fluid is more viscous at moderate to high Reynolds number if used in this situation? Air or Water? The flow is incompressible and has velocity V and size L. Homework Equations Re = inerial forces/viscous forces = rho*V*L / mu as Re approaches infinity...

Homework Statement What effect does a large positive dCp/dX have on the real viscous flow? This is for an airfoil design project using thin airfoil theory + vortex panel method. The Attempt at a Solution As far as I know Viscosity is independent of pressure, so the only thing I can...

In the design of a loudspeaker, one intuitively seeks a critically damped alignment. We must consider the electrical resistance of the coil, magnetic field strength, mechanical resistance, mechanical compliance, and mass (diaphragm + acoustic load) of the system. The electrical resistance...

Hey all, I am looking into the physics of an object moving through a viscous fuild. I have had a look searching google, but it only comes up with articles relating the terminal velocity of an object. Are there any detailed sources that anyone knows about? If so please post a link...

Which of the following is true in a streamlined flow of incompressible viscous liquid? A) When a fluid is in streamlined flow then there is transport of energy from one layer to another. B) The speed of flow at all points in space is necessarily same. C) The velocity of the liquid in contact...

viscous flows are always rotational because of shear stress that is exerted on the fluid element due to viscosity. what about the inviscid flows? can they be rotational ? if yes then what are the factors which makes the inviscid flows rotational?

The Navier-stokes equations have no definite understanding of how it works; does the incompressible viscous and inviscid flow have a definite understandings (Hannah and Stephens)

Hi all, I am new here, but in my (chemistry) research I have struck upon a problem that one of you might be able to help me with. I am interested to find an expression for the energy that it would require for an object to expand in a medium of known (dynamic macro-) viscosity. In other...

We push a ball through a viscous fluid with constant external force. As the ball moves, it compresses a spring. The spring resists compression with an elastic force f=kd, where k is the spring constant. When this force balances the external force, the ball stops moving at d=f/k. Throughout the...

Homework Statement Water (n = 1.00 10-3 Pa·s) is flowing through a horizontal pipe with a volume flow rate of 0.029 m3/s. As the drawing shows, there are two vertical tubes that project from the pipe. From the data in the drawing, find the radius of the horizontal pipe. Homework...

A 11.00 kg object starting from rest falls through a viscous medium and experiences a resistive force R = -bv, where v is the velocity of the object. The object reaches one half its terminal speed in 5.84 s. (a) Determine the terminal speed. 82.7 m/s (b) At what time is the speed of the object...