Fluid Definition and 1000 Threads

why the forces in pressure always taken perpendicular? and if they are taken then to which direction? and what about presure on a curved plane?

Hi When we talk about a fluid moving at low Mach numbers, it is said to be incompressible. But does this mean that the flow is incompressible (i.e., material derivate is zero) or does it imply that the fluid itself is incompressible (constant density)? If anybody has a reference (book...

Homework Statement Good evening. First post on this forum! The problem I wish to state would take too long to write by hand so I thought it best to do so via attachment. The question I am stuck on is part d and, in fact, part e also. Homework Equations All relevant equations are given...

Hi! When you are calculating ##\psi## or ##\phi## from the horizontal or vertical velocity components of a fluid's velocity, you end up with a constant ##C## carried along with the function. In my class, the professor just said something about them being arbitrary (I think..) and set them to...

1. Hi All I had a quiz in my fluid mechanics class with the question A ship model scale 1/25 is towed through seawater at a speed of 1m/s. A force of 2N is required to tow the model. Find the speed of the ship if the prototype is subjected to wave resistance only. 2. REm=REp...

Homework Statement We recently did an experiment involving the impact of fluid jet on both plane and cupped surfaces. See the diagram attached for the experimental set up. We were asked to 1) verify the conservation of momentum and 2) calculate the discharge coefficient of the nozzle from...

I have two cylindrical tubes connected at a 90 degree junction. One tube has a constant flow of a laminar fluid going through it and the fluid is saturated by a soluble particulate with a known concentration. The other tube has a much smaller radius, initially has no particles and is closed at...

Homework Statement The two-dimensional steady flow of a fluid with density ρ is given by v=K(-yex + xey) / (x2 + y2) where K is a constant (a) Can this flow corespond to the flow of anincompressible fluid? (b) Determine and sketch the streamlines of this flow. (c) Determine and sketch...

Homework Statement An incompressible fluid with density ρ is in a horizontal test tube of inner cross-sectional area A. The test tube spins in a horizontal circle in an ultracentrifuge at an angular speed ω. Gravitational forces are negligible. Consider a volume element of the fluid of area...

Determine velocity of a fluid -- not enough info given? Hi folks, I'm currently in an internship at Cassidian, and my supervisor has asked me to calculate the velocity of a fluid. I didn't spend too long on the subject, maybe an hour or two, but I wasn't particularly busy that day. I...

Hey all. I am an undergraduate math major in my third year who is planning to do a reading course in fluid mechanics next term. I have taken courses in rigorous advanced calculus, real and complex analysis, topology, and intro ODE and PDE. I would be taking a differential geometry course, which...

Homework Statement A hydraulic car lift has a reservoir of fluid connected to two cylindrical fluid filled pipes. The pipe directly below the car has a diameter of 1.8 m. the pipe o which the plunger acts has a diameter of 0.045m. the plunger is depressed a distance of 1.5m. How much does the...

Fluid Mechanics Question! Help needed :( Homework Statement It has been proposed that we could explore Mars with inflatable balloons. the density of the Martian atmosphere is 0.0154kg/m^3 (ignore that this varies with temperature). Suppose we make the balloons out of a thin tough plastic...

For the problem attached, I solved it and found the answer for part b : 80.21 s How to get sure or know if the answer is right or not. Thanks

Homework Statement Water travels through a pipe with a radius of 1 inch at a speed of 2 m/s. There is a nozzle at the end of the pipe with a radius of 1/4 inch. The pipe is horizontal and 2m above the ground. How far does the water travel in the air before hitting the ground? r1 = 1 in. r2...

How to find the dancy friction factor by using the colebrook white equation (not using the moody chart) ; to calculate the 1/√f = -2LOG[(e/d)/3.71 + 2.51/(Re*√f)] help please

Homework Statement A horizontally oriented tube AB of length ##l## rotate with a constant angular velocity ##\omega## about a stationary axis OO' passing through the end A. The tube is filled with an ideal fluid. The end A of the tube is open, the closed end B has a very small orifice. Find the...

Homework Statement A sphere of radius ##a## is submerged in a fluid which is flowing in the z-hat direction. There is some associated viscosity in the fluid which will exert a force on the sphere. Use symmetry to argue that the net force will be in the z-direction. Show that it will have the...

Homework Statement The horizontal bottom of a wide vessel with an ideal fluid has a round orifice of radius ##R_1## over which a round closed cylinder is mounted, whose radius ##R_2>R_1##. The clearance between the cylinder and the bottom of vessel is very small, the fluid density is ##\rho##...

I trying to come up with a way to measure the power output of an engine using a water pump, And I wanted some one to go over my math and check for flaws in my thoughts. My idea is to measure the flow rate and the pressure of the output of the water pump. Using this math to solve for power...

Hi guys, I studied mechanical engineering and I am currently a graduate student (turbulence modeling). I am interested in the more formal/mathematical aspects of fluid dynamics, which are mainly worked in mathematical faculties and I would like to know if someone knows/have an idea about...

hey pf! i am studying fluid mechanics and was wondering if any of you are familiar with a flow around some geometry? for example, perhaps a 2-D fluid flowing around a circle? if so please reply, as i am wondering how to model the navier-stokes equations. i'll be happy to post the equations...

Hello, I would just like some clarification on this... When you calculate "total" pressure at a depth in a fluid do you have to add on the value for atmospheric pressure?? Thanks, Molly :-)

hey pf! i am studying fluid mechanics and we are reviewing navier/stokes equations. we have gone over a few problems, but i could definitely use practice on more. do you all have any suggestions that include solutions, not just answers, so if I am stuck i can see how to solve? problems...

Homework Statement A block of mass 20 g sits at rest on a plate that is at the top of the fluid on one side of a U-tube as shown below. The U-tube contains two different fluids with densities ρ1 = 1070 kg/m3 and ρ2 = 650 kg/m3 and has a cross sectional area A = 4.6 * 10-4 m2. The surfaces...

I understand that as an incompressible fluid flows through a pipe with decreasing cross sectional area the velocity increases. This must happen for the mass/volume continuity equations to be true. Since the velocity is increasing though there has to be a net pressure on the fluid right? My...

Homework Statement The block of ice (temperature 0°C) shown in Figure P9.57 is drawn over a level surface lubricated by a layer of water 0.10 mm thick. Determine the magnitude of the force needed to pull the block with a constant speed of 0.50 m/s. At 0°C, the viscosity of water has the...

Homework Statement see the pic attached Homework Equations Newton's law of viscosity The Attempt at a Solution okay, i knew that , since the viscosity of the fuid in the second tube is low, it flows easily than the other, but i don't know which exact euation connects visocsity...

Homework Statement A uniform wooden stick of density d is completely immersed in water of density D (D>d). One end of the stick is free to rotate about a hinge which is attached to the wall of the container. In equilibrium the stick the stick makes an angle θ then tanθ is- (a)0 (b)d/D...

I am thinking that... if a tank of water which contains a small wooden block is kept in an elevator which is accelerating upwards from rest, will the block get more dipped or remains constant position with respect to water??

Resistance -- fluid resistance to ball motion A ball of mass m = 3 kg is falling from an initial height y = 3 m in an area where the acceleration due to gravity can be approximated as g = 10 m/s2. As it falls the ball is subjected to a fluid resistance of magnitude FR = kv where k = 6 kg/s. How...

Can anyone recommend me a book on Fluid Mechanics? I've been recommended Landau's book on Fluid Mechanics, but I haven't learned Statistical Mechanics which is required in his book.

So when a ball falls through a fluid in which it is submerged, it keeps displacing fluid as it descends, but the level of the fluid doesn't rise. So does the ball do work on the fluid? (Assuming there is no viscosity, the K.E would keep increasing, while potential energy decreases...that's...

Hey! So for Newtonian fluids, the shear-stress is given by \tau = \mu \frac{du}{dy} Now, let's assume you have water flowing horizontally in laminar steady state motion, where its surface is also moving. Above it is air. So if we disregard the friction from air, the shear-stress will become...

hey all im taking a graduate level fluid mechanics course. we are using a good amount of vector calculus (expected) and also tensor algebra, leading into the kronecker delta and Levi-Civita symbol (shockingly never saw these before, though implicitly used them). it seems linear algebra is...

Could someone recommend me a good Introductory Fluid Mechanics book? It's only an introductory course so it doesn't have to be too comprehensive at all. Thanks.

Hey! When a stream is steady-state, you can cancel the acceleration term in navier-stokes equation, right? so: \rho \vec{a} = 0 = - \nabla P + \rho \vec{g} + \mu \nabla ^2 \vec{V} But there are many terms in the total acceleration which are not dependant on time! The acceleration term in...

Researchers in fluid mechanics: "engineers", "Physicists" ? Dear all, I was reading the book "Turbulent flows" of S. Pope and I went to his website at Cornell and started to see his work. In case you do not know him, I can tell you that his work is 100% applied mathematics and fluid physics...

Dear all I am having a problem on circular flow of fluid. On all books I have read they say \frac{dp}{dr}=\rhov^{2}/r Which make sense by using infinitesimal square volume and take the force exert. But if I use a circular infinitesimal volume (which is usually the case for circular...

Homework Statement The ocean liner Titanic lies under 12500 feet of water at the bottom of the Atlantic Ocean. (The density of water is 62.4 lb/ft{}^3.) What is the water pressure at the Titanic? (Give your answer in both pounds per square foot and pounds per square inch.) Homework...

fluid mechanics question help!? Homework Statement Air flows through a horizontal duct of dimensions 300 x 300 mm with a velocity of 15 m/s. At position (1) in the duct a water gauge (water manometer) registers a hieght of 215mm. The duct bends downwards and reduces in size to 240 x 240 mm...

Homework Statement You are given an open-ended mercury manometer and asked to determine the pressure in a pipeline that supplies feed gas to a reactor. However, when you connect the manometer to the pipeline, you notice that the calibration markings in the leg that connects to the...

What is the prove for this formula, or in another way the provement of the dynamic viscosity multiplied by the shear strain will get us the shear stress,

Hi there, I just would like if someone could check over my work on my current homework assignment involving fluid dynamics. Homework Statement 1) Calculate the absolute pressure at an ocean depth of two kilometers. Assume the density of seawater is 1000 kg/m3, the density of air is 1.3...

Homework Statement Homework Equations The Attempt at a Solution Just checking if this is correct, and if the equation in part c implies that the flow rate out changes with time, or is just based off the initial height..I think it changes and therefore requires this integration. Also, I looked...

I was looking at a site which described the classic demonstration to illustrate how water pressure increases with depth (shown by punching three holes, one above the other separated by a few centimeters, in a container of water): "The smaller the holes, the greater the rate of flow from the...

I just read this, from a site dedicated to popularizing science: " ...think of air as being like water. If you have a garden hose and put your thumb over the end, the pressure increases and water sprays out. Same thing with air. Except the increased pressure is under a plane's wings and...

Homework Statement Consider a fluid between two plates. One on the bottom which is stationary, and one at the top which is moving at constant velocity V. The plates are separated by distance h. Does shear stress change as you move further from the moving plate? Homework Equations the...

Homework Statement It's a relatively simple problem I'm sure, but I'm a bit confused on how exactly to go about it: There are three parallel plates with water (viscosity of 0.8807 cp @ 30°C) between plates 1 and 2 (plate order of 1 on bottom, 2 in middle, 3 on top), and toluene (viscosity...

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...