Fluids Definition and 482 Threads

Some silicon products (like silicon greases) have different types of fillers added to it (like silica and carbon black) to give it certain properties. How these fillers are added/combined/"dissolved" to the silicon fluid?

Homework Statement A ball is dropped from a height 'h' above a tube containing oil. Describe what happens to the GPE when the ball has reached terminal velocity in the oil. Homework Equations KE = 1/2mv^2 GPE = mgh The Attempt at a Solution When the ball is dropped,if we ignore air...

Homework Statement Calculate "H" Homework Equations Bernoulli Manometry The Attempt at a Solution I have calculated that Q=0.06723 m^3 /s If I apply Bernoulli in the surface of the tank A and in out of the pipe, I have: H =(velocity in the final part of the pipe^2)/(2g). I have assumed that...

Homework Statement Homework Equations height of liquid above water level ##h=\frac{2T}{R\rho g}## for isothermal process :##PV##=constant And if ##P_0## is atm. pressure, and P is pressure just below the water level in capillary tube, then $$P=P_0-\frac{2T}{R}$$ The Attempt at a Solution...

I want to know if the velocity profile is uniform for viscous fluids or not ?

Hello, I'm a PhD student in medical biology and am doing experiments with bloodvessels. I've modified an existing technique and getting unexpected results (ofcourse..). I think it is due to a pressure difference but my knowledge of physics is inadequate to be sure. Ill give a short explanation...

Question with diagram: Relevant equations: Attempt : My question: Using my method I got the wrong force , not sure if in this situation I can use Q=A1U1 = A2U2, hence maybe that's why U2 = 195 m/s looks wrong/too fast? I continue to use momentum conservation in the x and y directions...

I know we need to use F = pgA(h bar), as that's what I'm given in notes and whatnot, but I can't for the life of me get this simple one done. Any help would be GREATLY appreciated as I have an exam coming up on this.

A sphere (with density less than that of water) is placed into 2 different cylinders. One with a spinning column of water and the other with a still column of water. Why does the sphere in the spinning column of water take much longer to float to the top of the cylinder? I was thinking about...

Homework Statement The initial separation of the pistons is 2cm. They are submerged in water at room temperature. I need to calculate the work required to have two pistons touch, find the volumetric flux of the water as a function of time, and the force at a given time Homework Equations...

Homework Statement Wooden qube with 12cm faces floating inside water and oil in 2 layers. The oil floats over the water. Water density: 1gr/cm cubed Oil density: 0.8 gr/cm cubed What is the mass of the cube. Homework EquationsThe Attempt at a Solution F(buoyancy) = g*(density)*volume , but...

Homework Statement An iron casting weighs 300 N in air and 200 N in water. What is the volume of cavities in the casting, if the density of iron is 7800 kg/m3 ? Homework Equations d = m/V Fg = mg The Attempt at a Solution I was not sure in the slightest of how to solve this problem. So I...

When a hose with running water is partially blocked with our finger ,the water comes out with a greater velocity. This is in agreement with the law of continuity in fluids which states that velocity of fluid is inversely proportional to the area of cross section. But when a running tap is...

Homework Statement A tube which is open at both ends is immersed in a beaker containing mercury. The top end which comes out of the mercury level is now sealed and then the tube is raised by some height such that some part still remains inside the beaker. The mercury inside the tube rises...

Hi there, I have set up a flow loop for a uni experiment that will teach other students about the bernoulli equation. The loop will use a few working section that will increase and decrease pressure due to diameter, velocity and height changes. I first set-up my loop with the pump at the end...

When a Vessel of water is under free fall and there is a hole in the side of the vessel, why does no water come out of the vessel? (its given in my textbook that pressure exerted on sides of vessel is zero. But what does the horizontal force have to do with the vertically acting force due to...

Homework Statement A cube of ice is floating in water such that some part of the ice is submerged. Oil is poured on the water.( so water on the bottom, oil on top and ice in between). When the ice melts completely, the level of oil-water interface ______(rises/falls) and the top level of oil...

Homework Statement Derive an analytical expression for the permeability (k) of the structured porous medium (which is a size selective filter) constituted by a periodic array of cylinders of diamter d separated by a distance h = 1.8d Homework Equations Q=k*(μ/A)*(Δp/L) Q = volumetric flow rate...

Homework Statement dynamic viscosity 1 = 1125 2 kgf-s / m2 , dynamic viscosity 2 = 62.5 2 kgf-s / m2 , Areas: A1 = 20 cm2 , A2 = 50 cm2 W1 = 15 Kgf, W2 = 40 Kgf. The block (2) is displaced downwards with a constant speed of 80 mm / sec, whereas linear velocity distribution determined: 1) The...

It's about shear stress and strain. We are talking about Newtonian fluids, a situation where we are lubricating a rotating shaft with oil. I cannot understand what we are measuring that we use as the strain. SOLIDS. As far as I know we can say: Stress (F/A) = G x (Δ l / l) Where G is shear...

Homework Statement (1)The gas inside a spherical bubble expands slowly so that its radius is increases from R to 2R. Atmospheric pressure is ##P_0## and surface tension is S. The work done by the gas is ___________ Homework Equations work done against surface tension ##W_t = S.\Delta A## where...

Homework Statement Derive a mathematical relationship which encapsulates the principle of continuity in fluid flow. Homework EquationsThe Attempt at a Solution Imagine we have a mass of fluid ## M##, of volume ##V##, bounded by a surface ##S##. If we take a small element of this volume...

Homework Statement Attached document Homework Equations m(flow)*(v1-v2)+P1A1-P2A2 The Attempt at a Solution I did a mass balance to plug into the momentum balance, but I am not getting the final equation correct.

So I've been trying to do some physics puzzles and I've come across this in a book called "200 puzzling physics problems." The solution in the back makes no sense to me and I can't seem to figure it out by myself. Can anyone help me?

Ok, so for the derivation of the Navier Stokes, the conservation of momentum through a control volume (CV) is Time rate of Momentum Change in CV = Time rate of Momentum Change into CV - Time rate of Momentum Change Out of CV + Sum of External Forces Why is Sum of External forces in there? I...

1.The problem I have been facing is understanding how a straw exactly works ?? I know the general, conventional solution given to this problem by the principle of working of a barometer, but I think it has a serious loophole. 3.They say as a vacuum space is created in the straw due to our...

Homework Statement a water filled symetrical container has four pistons , one on each side of area A to keep water in equilibrium Now an additional force F is applied to all four pistons . then increase in pressure at the middle of container will be: Homework Equations pascal law: change is...

A body is capable of remaining stationary inside a liquid in a closed box (that means its density is same as that of liquid) . If the whole system is placed on inclined plane and allowed to slide down then: 1. body moves up relative to liquid 2. moves down relative to liquid 3. stationary wrt to...

I’ve read that most comoglocial fluids can be modeled as perfect fluids. And that most perfect fluids obey ##p=w/rho##. I’m wondering (had a look around and can’t seem to find) two things: i) whenever ##p=w/rho## is obeyed does this always give the 3 descriptions of the universe – 2 open...

Homework Statement This problem pertains to the drinking straw trick. You decide to place your finger over a 20.0cm straw. 95.0% of the straw is filled with water, while the top is full of air. Treating the straw as an ideal gas, compute fraction of the straw that is filled with water when the...

What happens when you have more than one hole in a vessel containing liquid? Can you help me finding the velocities at different holes if they are at some height from level of liquid at a particular instant? I know what happens when you put a small hole in a tank containing liquid at a height h...

If I have a U-shape wire frame and it contains a straight sliding wire and I dip this in soap, a film forms between the sliding wire and the boundary of U shape frame. Why is the force due to surface tension F = 2Tl where l is length of sliding wire? They say there are 2 layers in contact...

Homework Statement Consider a simple model of a free-standing dam, depicted in the diagram. Water of density ρ fills a reservoir behind the dam to a height h. Assume the width of the dam (the dimension pointing into the page) is w. (a) Determine an equation for the pressure of the water as...

Hi, This problem has been driving me mad! Can anyone simplify the physics of this problem? Because I can't solve due to to many unknowns. Question ref: Engineering Materials, Benham, Crawford & Armstrong. Please refer to attachments.

Wondering if someone could link me to a derivation of this formula? It's on the Wikipedia page for the no-slip condition. u - u_wall = β ∂u/∂n β = slip length n = coordinate normal to the wall

Homework Statement A rock is suspended by a light string. When the rock is in air, the tension in the string is 35.7N . When the rock is totally immersed in water, the tension is 25.9N . When the rock is totally immersed in an unknown liquid, the tension is 19.6N . Homework Equations Density =...

So mathematically I understand that divergence of curl of something is zero. However, talking specifically about vorticity, this is what it seems to imply to me: When there is vorticity in a fluid, the tiny particles spin around their own axes, so a net circulation is formed around the surface...

1. Calculate the force needed to move the wire in the figure (Figure 1) if it holds a soapy solution (surface tension is 0.025 N/m) and the wire is 16.0 cm long. Express your answer to two significant figures and include the appropriate units. 2. γ(surface tension) = F (force) / l (length)...

Homework Statement Daphne goes to the kitchen for a glass of water. She turns on the faucet so the stream of water is laminar flow. She notes that the diameter of the water steam decreases with distance below the faucet assuming that the water exits the faucet of diameter D with speeds v0...

Hey guys, I've been doing a lot of research looking for a fluid that has a high expansion ratio that does not leave the liquid state. the idea is that the fluid could either: - using heat will expand and contract using hot and cold cycles - using electricity (not necessarily needing...

Hi everyone. So i have a simple problem and its really confusing me, although i think i might have been staring at the page too long. I have a pipe which has 4 inlets and one outlet; via air being pulled through via a centrifugal pump. Think of the inlets as pulling air from atmosphere...

$$\begin{equation} 0 = ({\rho}_m + P_m)u^{m}_iu^{m}_j + \frac{4}{3}{\rho}_ru^{r}_iu^{r}_j \end{equation}$$ where i,j = 1,2,3 and different. That is the off-diagonal elements of the tresstensor for matter fluid and radiation fluid. The energy conditions imply that ##\rho_m + p_m > 0## and...

If a fluid is compressible, will the density be directly proportional to the pressure? (I'm sure there's a limit where an increase in pressure stops producing a change in density, but I'm talking about for more "normal" (smaller) amounts of pressure.)

Homework Statement A solid sphere of aluminum (density 2.7 g/cm^3) is gently dropped into a deep ocean. (The density of ocean water is approximately 1.03 g/cm^3.) Calculate the sphere's acceleration at the point where it is completely submerged into the ocean. As the sphere drops deeper...

Homework Statement Small part of fluid which in the moment ##t=0## was at the point ##(X_1,X_2,X_3)## in some other moment is in the point ##(x_1,x_2,x_3)##. Where x_1(t)=X_1 x_2(t)=X_2+\sin \pi t\sin \pi X_1 x_3(t)=X_3 We know that the piece of the fluid is in the t=0 in line which connects...

Homework Statement Which of the following phases is capable of permanently withstanding a force perpendicular to its surface? A. Gas B. Liquid C. Solid D. All of the above Homework Equations The Attempt at a Solution I understand that the answer is D. However, what does...

Hi, I get two contradicting sections of the book "Concepts in Thermal Physics": Earlier in the section they used the grand partition function to derive the mean occupation number ##<n_i> = -\frac{1}{\beta}\frac{\partial ln Z}{\partial E_i}## Later in the section, they said ##<n_k> =...

Homework Statement The Euler equations for ideal compressible flow are given by \partial_t v + (v\cdot \nabla)v = g-\frac{1}{\rho}\nabla p \\ \partial_t \rho + \nabla \cdot(\rho v) = 0 In my book these are written in terms of the small-value expansions \rho = \rho_0 + \delta \rho, p = p_0 +...

I am working on this project for Diff eq's and I seem to be stuck. i think I am messing something up but I need a fresh pair of eyes to show me where it is. imgur: the simple image sharer imgur: the simple image sharer (this is the same page as ^ just scrolled down) imgur: the simple image...

I was reading an example problem in my fluid mechanics textbook that talks about the difference between liquids and gases. I am not sure why this is the case, if someone can explain that'd be great. So the problem is about two coaxial cylinders that rotate. There is a fluid in the gap between...