Fluid mechanics Definition and 698 Threads

Homework Statement "Suppose that a liquid has an appreciable compressibility. Its density therefore varies with depth and pressure. The density at the surface is ρ0 (a) Show that the density varies with pressure according to ρ=ρ0ekp where P is gauge pressure at any depth and k is the...

Homework Statement Given: Water flows through a 15.24m long, 1.6cm diameter hose. pressure at the outdoor tap = 275.8kPa volumetric flowrate, Q = 7.5e-4 m^3/s (i.e. 7.5L for 10 seconds) viscosity of water, μ = 0.001 Pa*s density of water, ρ = 1000 kg/m^3 Look for: the roughness of...

Homework Statement Here is the question along with my attempt: As you see in my second equation there are two unknowns, A_out and dm/dt. I think my problem is that I don't exactly understand the equation. dm/dt is the net mass flow rate. For example if dm/dt is a positive number then there...

We are beginning a project in my Intermediate Fluids class to make a program that can do aerodynamic analysis on an air foil. First, given any three nodal coordinates (x,y) of a triangle, we must write a program to compute its surface vectors and area of the triangle. The nodes will be in...

Can anyone give me some advice on where I should take my points of reference when using bernulli equation. I know the point will vary according to the problem, but can one say, always begin looking for this and that and apply the equation... Then move to this and that, etc

Hi all, For an exam I'm required to be able to plot the PDF of a fluctuating velocity function, say u(t)=sint(wt), using what they call the "graphical technique", but handily I can't find it anywhere in the lecture notes, and I'm struggling to find anything with a standard Google search...

I've rencently been thinking about several systems related to fluid mechanics, and I've asked myself the following question: If I have a cylidrical tank with a small hole in the bottom (the surface area of the hole is small in comparison with that from the tank) and I'm filling the tank with...

Homework Statement A shaft of diameter 74.9mm rotates at 1400rpm in a bearing which is of diameter 75.03 mm and 75mm in length. The annular space between the shaft and the bearing is filled with oil of viscosity 0.096 kg/ms.By assuming a uniform velocity gradient in the oil, determine the...

I am interested to know what book(s) others would recommend to someone aspiring to learn fluid mechanics from and what kind of preparation would be required for that book. I am an undergraduate student and have completed courses in single and multivariable calculus, linear algebra, ordinary...

fluid mechanics: defition of "shear flow" [rate of deformation tensor] I'm studying old undergraduate chemical engineering notes for an exam in grad school. Can't recall what this really means, can anyone explain to me what "off-diagonal elements" means and why the trig function velocities...

Hi, I am trying to work with the problem of keeping a solid body at equilibrium over an orifice. To see what I mean ( not necessarily a sphere could be a cube or something like that as well ) please look at the image I have attached. I am trying to work with the sphere case first and then...

Homework Statement A cork is held at the bottom of a bucket of water by a piece of string. The actual depth of the cork is 0.713786 m below the surface of the water. If the density of the cork is 157 kg/m3 and the volume of the cork is 3 cm3 , then what is the tension in the string...

I'm just a bit lost on how to find the change in pressure. I've posted a picture of my work thus far.

Homework Statement Hi guys, I'm pretty new here, and long story short, I'm struggling a bit on a fluid mechanics question I've been doing for some revision. A shaft 70 mm in diameter is being pushed at a speed of 400 mm/s through a bearing sleeve 70.2 mm in diameter and 250 mm long...

Homework Statement A velocity field is given by \vec{V}= [Ax^{3} + Bxy^{2}]\hat{i} + [Ay^{3} + Bx^{2}y]\hat{j}; A=0.2 m^{-2}s^{-1}, B is a constant, and the coordinates are measured in meters. Determine the value and units for B if this velocity field is to represent an incompressible flow...

Homework Statement A large cylindrical tank has a hole of area A at its bottom. Water is poured in the tank by a tube of equal cross-sectional area A ejecting water at the speed v a)The water level in the tank will keep on rising. b)No water can be stored in the tank. c)The water level...

Homework Statement A piece of wood is floating in water kept in a bottle. The bottle is connected to an air pump. Neglect the compressibility of water. When more air is pushed into the bottle from the pump, the piece of wood will float with a)larger part in the water b)lesser part in the...

This is the question The flow of a fluid between two large flat parallel plates normal to the y direction is fully developed and steady. The plates are a distance 2h apart in the y direction and the velocity profile, assuming y=0 is at the midpoint between the plate is V(y) = V_0(1-(y/h)^2)...

Can please anyone solve the following question in details... A cylindrical object of outer diameter 10 cm height 20 cm and density 8000 kg/m3 is supported by a vertical spring and is half dipped in water. Spring constant is 500N/m. (a) Find the elongation in the spring in equilibrium...

Hi, I am experiencing a little bit of trouble grasping the concept of vector fields in fluid mechanics: If the vector V = u i + v j + w k, where i,j,k are unit vectors in the x,y,z directions, then how can u,v,w be functions of x,y,z,t? I.e. if say v is in the y direction, then how can it...

Hello, I'm new to the forum. Does anyone have any suggestions for doing well on Fluid Mechanics? I got a 34 on my previous test (class average was a 35..). Any help would be appreciated. Ideally, I would love to find something like mech movies for mechanics of materials. My biggest...

I'm interested in making a larger-scale French Press (VIDEO, go to :30) It has a mesh-screening filter that keeps the coffee grounds contained when you push down. I'm theoretically using a large bucket, like those 5gal buckets at Home Depot, with the dimensions shown below. And...

Hello, I posted on college confidential and they advised me to come here. So here's my questions ! I'm currently a French student in fifth year of higher education (physics/engineering) and I'd like to do an internship in a US lab for 3 months. I currently have some opportunities : -...

Fluid Mechanics --Momentum Equation Homework Statement A large weigh tank is to be used in the calibration of a flow metre. Measurements of weights as a function of time are to be made. Water enters the tank vertically from the flow metering system at a speed of 20 ft/s through a 1.5 in...

Please see attached. I'm pretty sure i did the problem right, but I'd like to check with the great minds of physicsforums. Summing up flow rates and inlet and outlet gives: 1500+1200=2700 gal/min 2700gal/min= area at exit *Velocity at exit 2700 gal/min * (1ft^3 / 7.48 gal) ( 1min / 60...

This is not a homework problem, but an example that was demonstrated that I am confused about. Sorry if it should've been in the other forum nevertheless. I understand the mathematics of the derivation and the result; but I'm having difficulty reconciling this against common experience with...

Attached the problem. The TA for my class makes up all the damn homework problems, but she has a habit of leaving out important information on every single homework assignment. Sorry for the rant, just had to vent a bit. Unless they want all this in variables, I don't see a way to get a # for...

Homework Statement I've attached the problem I'm kind of lost as to how to even start this problem. For part ) I think my first approach is to sum up forces in the vertical direction. Which would yield F-W1-W2=ma=0 Where: F=buoyancy force W1=weight of submerged volume of oak...

Homework Statement http://imgur.com/vXkg0 Homework Equations Fw=γAH Ycp=bh3/(12)(h/2)b + (h/2) The Attempt at a Solution I found the angle of the gate from the horizontal to be 53.1 degrees. Using this, I found y to be 2.5m and H (vertical distance to centroid) to be 6 m...

Water at standard atmospheric pressure and temperature fills a sealed, rigid container. If the temperature of the water is increased by 50°C, what is the pressure? V = volume, P = pressure, T = temperature Coefficient of compressibility, kappa = (-1/V)(dV/dP) Coefficient of thermal...

Homework Statement I attached the problem. Please check my work. Homework Equations The Attempt at a Solution Density of oil=.92*1000=920 kg/m3 Density of vinegar=1010 kg/m3 Height of oil=3*.0254=.0762 m Heigh of water=.127 m a) Gage pressure at...

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 Attached. I am working on part (i). What is the resistive force? Shear stress= μ*(du/dy) = μU/l = F/A Since the force is up and down, it causes a shear stress, thus area is parallel to the force and thus it is the 4 faces B*L Thus, A=4*B*L → F=μ*U*A/l =...

I'm not sure if I should have posted in the advanced section, but this is for the class "fluid mechanics" which is an upper division course. However, the material I'm asking is mainly introductory stuff. Determine the dimensions of dP/dx. Where P is a force and x represents distance So...

Homework Statement Homework Equations I am having some trouble starting this problem. At first look I would say that a conservation of mass will give V1*A1=V2*A2 for steady state incompressible fluid. Then I would solve for A2 and relate the two diameters but I don't have the velocity...

Hi folks I am currently doing a question in fluid mechanics and i need some help rearranging formula to solve the equation... I have everyhting i just can't seem to figure how to make u( Velocity) the subject of the equation... The equation is μ = Fx/uA Thanks in advance Eddie

Dear all, I want to know the meaning of end-pinching in fluid mechanics. Can someone provide me with the information?

A liquid atomizer has the configuration shown in Figure Q5(http://img822.imageshack.us/img822/8543/figure5.png ). The liquid is accelerated through the nozzle and impinges on a cone attached to the nozzle by a thin rod. The nozzle is circular in cross-section and coaxial with the rod and cone...

Suppose I have say a 40' long 3/4" garden hose stretched out linearly on a level surface. One end is attached to a faucet with maybe 30 psi. At 10', 20', 30', and 40' there are small vertical pipes from which will shoot water when the faucet is turned on. The end of the hose is capped. There's...

Homework Statement Consider the steady flow of an incompressible viscous fluid down an inclined plane under the action of gravity. The plane makes an angle \alpha with the horizontal. The fluid is infinite in the z-direction (x is down the plane and y is normal to the plane). Look for a...

Homework Statement Spanish galleon is about to be boarded by bloodthirsty pirates in the shallows of a Caribbean island. To save a box of treasure on board, the captain orders his crew to secretly toss the box overboard, planning to come back for it later. The rectangular box is waterproof and...

I am working on a project at an internship this summer regarding flow rates of a certain system that is used to test flow rates on tools, and it requires a bit of a hefty explanation. I need to increase the current flow rate (1232 GPM) to the desired flow rate (1800 GPM) because some of the...

I am goin to study fluids mechanic next year, and I want to prepare for it, so I found the cours that corresponds to it, it is translated to english nd linked below. anyway, I want to know or if somebody can lead me to math courses that it is related to fluid mechanics, coz I need to learn it...

I have a question based on this little diagram I whipped up! http://i.imgur.com/2sLeQ.jpg Will the 25 PSI (generated by a pump) applied to the curved surface on the bottom of the piston exert a higher force upwards to oppose the downward force on top of the piston? A detailed...

Homework Statement Homework Equations Provided above The Attempt at a Solution Piezometric head is defined as the pressure head plus the elevation head, correct? But how does having a high piezometric head tell you about the fluid flow? Since the diameters are equal, the area's are...

A jet of water 70mm in diameter moving with a velocity of 25m/s impinges tangentially on a stationary blade which deflects the jet through 130o. (a) Find the resultant force on the blade, in magnitude and direction. (b) If the blade has a velocity of 5m/s in the same direction as the jet and...

Homework Statement You are given a 10cm Cube of aluminum with Density of 2700kg/m is submerged in water and the weight in water is 13N. If a cavity exist how big is it? Homework Equations The equation i used were B = V * P_water * g to find buoyancy. To find the enclosed cavities i...

Hi First off I'm not a student, this is purely a curiosity question In pascals law classic drawing if you added a piston inside one of the cylinders what would happen? I've added a drawing to clarify I'm totally split on what the answer is, Pascals law seems to state the pressure on...

I know the main focus of Civil Engineers are the strength of the structures. I also know that Fluid Mechanics and Hydraulics are important in designing dams or other structures related to fluid. But what about to Building structures? How is it important?

Homework Statement A horizontal bend in a pipeline conveys water at a discharge at 1000l/s gradually reduces from 600mm to 300mm and deflects the flow through an angle of 60 degrees. At the larger end the pressure is 170000N/m^2. Determine the magnitude and direction of the force exerted on...