Fluid Definition and 1000 Threads

I am looking into hydrostatics, but am now very confused about what has to remain constant in an incompressible fluid. I initially thought that pressure has to be the same all throughout the fluid, and that this is the reason why you can use water or oil when raising a car- you apply a small...

Homework Statement a) A orifice, diameter d (m), in the walls of a tank discharges water under a head, h (m), subjected to gravitational acceleration, g (m/s2). If the fluid has density, ρ (kg/m3)and viscosity, μ (Ns/m2), show that the quantity of fluid Q (m3/s) flowing out of the tank may...

I was wondering if I could get you guys advice on something. My school only offers fluid mechanics every other Fall. This spring I'm taking physics 1, calc 2, and chem 2. In the fall I'll for sure be taking physics 2, and calc 3, I could take rigid body mechanics and experimental techniques, but...

In solving the Navier Stokes equation, the typical boundary condition imposed on the tangential velocity at a solid surface is that of no-slip. However, it is known that for gaseous flow there always exists a non-zero velocity near the wall, especially at relatively big Knudsen number. Is there...

Can anyone tell me how significant are entrance effects for a fluid entering a circular pipe? Like the fully developed region, laminar region etc. comparison between these regions...

I completed 4a successfully, and with 4b, i have 2 queries: a)why can't I let Reynolds # equal to 2.19 x 10^5 (from part a) then simply sub v=4 instead of 5m/s and rearrange for viscosity? I tried it this way first and got a very wrong answer. Why do we, essentially, need to work backwards to...

see I worked through 3a) and I was comparing answers, I saw that they omitted v2 (5m/s) their explanation was because it was "defined in the question" I'm not sure what that means 3)b I tried understanding what's going on but I am clueless unfortunately, how exactly did they get 12.1m ? Where is...

1. Water is flowing in a pipe at 5ms-1, the end of the pipe is held vertically and discharges into the atmosphere, the velocity of water discharging from the pipe is: a=0.25 b=1.3 c=5 d=25 2. The water in the question above will rise to a height in metres of: a=1.3 b=0.25 c=25 d=13 I will be...

Homework Statement It is a question I asked to myself because I need to reply to another one. I imagined this case: http://imageshack.com/a/img912/7730/R964Vq.png The step2 needs the energy E1, the step3 needs nothing because the gravity is 0 (I imagine the device between the Earth and the...

< Mentor Note -- thread moved to HH from the technical engineering forums, so no HH Template is shown >[/color] Pics are attached, my concerns are with question 4 and 5. For q4 -which way is flow? How do we know? -the working then goes on to say that energy loss is compensated by increasing...

Thinking of individual fluid particles, my guess is that the "force" is simply particles backing up somewhat at the constriction point and contributing a higher proportion of collisions on particles ahead of them in a direction down the pipe. As the average movement of the particles is directed...

Hello :) My question concerns a control volume with a changing area. The momentum equation: p1A1-p2A2 = ṁ(V2-V1) is applied to the control volume. The image shows the equation found when applying the above momentum equation to the control volume: The bit I'm having difficulty with is the part...

Homework Statement A fluid flows through a pipe. The flow varies with time. We want to estimate the volume of fluid (##V##, in ##L##) that passes through the pipe between time ##t = 10 s## and ##t = 14 s## (i.e. we want to integrate the flow between these times). The available instrumentation...

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...

Homework Statement A bead of radius R(=5 μm) is trapped by an optical beam and moved through a viscous fluid at a speed vd of 20 μms-1. If the viscous drag is given by Stokes law: F_{d}=6\pi \eta Rv_{d} obtain an expression for the laser power (intensity). If the process only has an...

Homework Statement A block of mass m is connected to a massless rod and plunger of area A1 on a cylindric container of water. At the bottom of the container there is a pipe that leads to an opening of area A2 where the water pours out at a velocity v. The block starts at rest with the...

A body moves through a fluid, a retarding force due to turbulence may be experienced. In case of a sphere of radius R moving with speed v through a stationary fluid of density p which it at rest, this force is given by F = kp (R^2) (v^2) k is a constant. Why F is proportional to kp (R^2) (v^2) ?

Homework Statement The tank shown in the figure is filled with water and fastened to the ground. There is a small opening on top of the semi-spherical part of the tank. a) What is the magnitude of the horizontal force on the screws? Explain using a free body diagram. b) Consider the proper...

And it seems like it's so straightforward for everyone else, which is incredibly frustrating. It's about the relationship between pressure and flow rate of a fluid moving in a pipe or closed system. Often what I've heard is, they have an inverse relationship...but then there are cases where...

Hi, I'm trying to measure the steady state velocity field behind the wake of a bluff body in the wind tunnel. My uni is equipped with 4-hole cobra probes which is capable of receiving flow within a 45 degree cone of acceptance. As the base of a bluff body dominated with re-circulating flow...

Hi all, Recently did a lab experiment where we had a nozzle pointing vertically upwards at a flat plate normal to the direction of the flow of air. The plate had a spring gauge on it so that the force of the air on the plate could be measured. The plate was moved to various distances above the...

Homework Statement Find magnitude of net upward force on a cube in terms of l, ρ (rho), g and h. then show that h = m/ρl2 A solid cube, mass m, side length l, is placed in a liquid of uniform density, ρ(rho), at a depth h0 below the surface of the liquid, which is open to the air. The upper...

Homework Statement A solid cube, mass m, side length l, is placed in a liquid of uniform density, ρ(rho), at a depth h0 below the surface of the liquid, which is open to the air. The upper and lower faces of the cube are horizontal. Find the magnitude of force, Fs, exerted on each vertical...

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...

Homework Statement As shown in the figure, if the pipe net work is shifted bodily by 10m vertically up the tank, and all the other conditions remain the same as the previous figure. Will the volume flow rate change? Or I rephrase it as, in the calculation of elevation head of pipe flow, is the...

I am referring to this article:http://www.quantamagazine.org/20140624-fluid-tests-hint-at-concrete-quantum-reality/ Only a handful of phycisists (John Bell being one of them) took the Bohm-interpretation of QM seriously, given it had no scientific falsification, Are those views likely to change...

Homework Statement A vertical jet of water of 3cm in diameter impinges upon a horizontal flat plate with a velocity of 4m/s, and all of the water spreads out horizontally. Find the force exerted on the plate. Homework EquationsThe Attempt at a Solution I am not 100% sure how to tackle this...

Hello guys, I'm writing to get some help on an exercise I've been thinking but I can't get to solve. I have to write the code for the Example 8.5 of the book White, Fluid Mechanics. Here is the problem and the solution I have to obtain. It is about one duct that has three sections in which I...

Hi everyone, I'm new here and I have a question to all the physicists out here in the forum. I'm an aerospace engineering student and there is something that has been bothering me for quite a while. That is: Why does the static pressure of a fluid in motion change? Don't get me wrong, I'm...

I have been trying to fully understand this concept of Bernoulli's Principle , the Venturi effect and fluid velocity and energy. I need to grasp this to develop an idea that I have been working on. 1. As water is forced down a narrowing pipe, as the pipe gets more narrow, it means it losses...

I want to go to physics grad school, but I also want to be ready to go to into CFD for industry if academia doesn't pan out - what area of physics would prepare me best for that?

So Volume Flow Rate (Q) = (P2-P1)/R where R is the total resistance of the system. R is directly proportional to Length and inversely proportional to surface area, and the inherent resistance (viscosity) of the fluid. But R =nL/r^4. r^4 rather than r^2. So there has to be another factor...

1. Homework Statement Calculate the torque on the dam about the origin (Picture attached) due to the pressure force of the fluid. Homework Equations Pressure force is correct (dF) The Attempt at a Solution [/B] I have solve it; however, I am not sure if I calculated over the origin asked...

Basically, I'm modelling the flow of a "coating" process -- a fluid flow between a flat moving plane and a stationary cylinder, 2D, cartesian coordinates. Subscript 0 is the at the minimum height b/w the plane and the cylinder, and subscript c is at the point at which the flow leaves the moving...

Homework Statement Hi guys, I need to explain the outlier point here, which has been shaded in the excel spread sheet when comparing the two dimensionless groups, The dimenionsless group, drag-coefficient is given by Drag/(density*V^2*D^2) and dimensionelss group, spin parameter, is given by...

Lately I have found an interest in fluid mechanics and found Landau's Fluid Mechanics text. Despite know it wasn't introductory, I decided to give it a try before deciding I need something before it. Is there a science-like (as in not engineering) fluid mechanics textbooks that would help...

Homework Statement The figure shows a schematic drawing of an open ended well-type manometer. Attached to one end of the manometer tube is a well (a reservoir with a higher crossectional area compared to that of the tube). The manometer is filled with a fluid with an SG = 2.95. The manometer...

I'm curious as to roughly how many mechanical engineering graduates have found jobs where they utilise the knowledge they gained in fluid mechanics, thermodynamics and heat transfer as part of their university degrees. Reason I'm curious is because, from my class, I'm not actively aware of...

Hello everyone, I have a physics question on pressure exerted by a fluid onto an object (see attachment). I would like to know how I can calculate the total pressure exerted on an object in a vessel by flowing fluid (water) with an open outflow. It has been too long since I took college...

1. A sphere 1 ft in diameter is moving horizontally at a depth of 12 ft below a water surface where the water temperature is 50F. Vmax = 1.5Vo, where Vo is the free stream velocity and occurs at the maximum sphere width. At what speed in still water will cavitation first occur? Given: speed...

Hi PF! I was reading lecture notes from a university and I stumbled on this situation: We have a hypothetical 2D inviscid, steady, uniform and parallel, potential flow, described by the velocity vector ## \vec{v} = <u,w>##, with ##u= U[z]## and ##w= W[z]##. It is moving parallel to a...

Dear Friends, I need some ideas on a problem I am facing at work. I have attached a sheet with has a rough picture of scenario. I urge you to please keep open the picture while reading my problem. Problem:- There is a small wall in a water stream. Due to the small wall the water stream upside of...

I have a pipe with regular diameter connected to a tap, the water comes from public supply, I assume that public supply can vary on pressure and flow rate. How can I guarantee that I allways get the same volumetric flow rate at the end of the pipe? Will a pressure reducer be sufficient? Thank you!

Homework Statement Write down the complex potential for a source of strength m located at z=ih and a source of strength m located at z=-ih. Show that the real axis is a streamline in the resulting flow field, and so deduce that the complex potential for the two sources is also the complex...

Hello, I would like to ask if its possible to apply pressure through fluid on a curved soft tissue such as silicon to measure the strain by using sensors (and what kind) such as shows in the attached image? If those were pressure sensors would they all show the same pressure or would the change...

Hi I just started on my fourth year of a masters degree in mechanical engineering, and I got this fluid mechanics course that is nothing like anything I have had before. This course is based on finding expressions using Stokes equations. Combining and deriving momentum, continuity and energy...

Hi there, I have a double-barreled question for you all. So I have two pipes connected to each other. The first pipe is 0.64cm and has a Re = 5000, the second pipe is 4.5cm and has a Re = 700. The two are connected so that the gas expands from the the first pipe to the second. Now, I wish to...

Homework Statement Two tanks are connected via a capillary pipe, with one tank over the other. The speed in which the liquid flows from the upper tank to the lower tank is 3472 cm/min. The height of the liquid inside the upper tank is 30cm from the bottom of the tank. The capillary pipe sticks...

Homework Statement Ball A is dropped from the top of a building. One second later, ball B is dropped from the same building. As time progresses, the distance between them A) increases. [<-- Correct Answer] B) remains constant. C) decreases. D) cannot be determined from the information given...

Hi All, Recently we've been working on the distinction between the Eulerian and Lagrangian approaches in Fluid mechanics. I understand the simpler examples like a running stream of hot water etc. However one example is really tripping me up. So what's confusing me is that in analyzing...