Fluid mechanics Definition and 698 Threads

Homework Statement If in an open water channel, the approach speed of an incompressible ideal fluid, of constant depth h1, is not too large, a small bump in height H (H<< h1) in the base of the channel will cause a dip Δh (Δh << H) in the water level directly above it, such that h1 = Δh + H...

Lagrange & Euler formalism How we get relation (\frac{\partial T^{(L)}}{\partial t})_{r_0}=(\frac{\partial T^{(E)}}{\partial t})_{r}+\frac{\partial T^{(E)}}{\partial x}(\frac{\partial x}{\partial t})_{r_0}+\frac{\partial T^{(E)}}{\partial y}(\frac{\partial y}{\partial...

The problem: A canal cut in rock (n= 0.030) is a trapezoidal in section with a bottom width of 6.10m and the side slopes of 1 on 1. The allowable average velocity is 0.76 m/s. What slope will produce 5.66 m^3/s? The books answer is 0.000675 from the mannings equation V=(1.486/n)R^2/3 x...

Hi, i am having difficulty with a question because i cannot seem to get the right answer. i don't think i am far off i just know i go wrong somwhere and if you could point that out it would be great. the question is attatched. for the first part i find the equations of the lines of the two sides...

I'm taking fluid mechanics in the fall, and I hear the professor is a real pain. I want to prepare over the summer by getting exposure to the material. I'm in an undergraduate program, and have all the math I need (though it's been a while since differential equations, so I'm actually...

Homework Statement Given: water at 20°C flows through a 3cmID smooth brass tube at 0.002 m^3/s. Homework Equations V=Q/A f=64/Re Re=VD/(nu) The Attempt at a Solution V=Q/A=(0.002 m^3/s)/((∏/4)*(0.03 m)^2) = 2.829 m/s Re=VD/(nu) = (2.829 m/s)*(0.03 m)/(1x10^-6 m^2/s)=84882.64...

I'm having a little problem with my book as I was reading about fluid mechanics. The book seems to have skipped a bit of some crucial part (at least for me) during the derivation for fluid pressure at certain depths (where the weight of the fluid is not neglected). Here, I'll try to reconstruct...

Hi all, Sorry if this topic has been done a lot. I'm not very good at searching. It seems to me that fluid mechanics is left to engineers and mathematicians (in particular, applied mathematicians? I guess they study the concept of flow?) What gives? Engineering department here at Cornell has...

Homework Statement Fluid Mechanics problem: http://i.imgur.com/dlAO6.jpg SHM of spring problem: http://i.imgur.com/7AOMR.jpg Homework Equations Fluid mechanic problem; Bernoulli's principle A1v1=A2v2 v= velocity A= cross sectional area R= flow rate SHM of spring problem; x(t)=Acos(ωt+∅)The...

Homework Statement A can of Coca‐Cola has a small pinhole leak in it. The Coke sprays vertically into the air at a height of 0.5 m. What is the pressure inside the can? ρ = 1.11 g/mL Homework Equations Bernoulli: p1/ρ + (v1^2)/2 +g*z1 = p2/ρ + (v2^2)/2 +g*z2The Attempt at a Solution I've...

When I am reading the paper in fluid mechanics, I found a paragraph and two equations: "Since the fluid is considered Newtonian and incompress- ible of density ρ and constant viscosity μ, the dimensionless mass and momentum balance equations are:" \nabla \cdot \mathbf{v} = 0...

Homework Statement The problem: There is an illustration and the question is to find the force F to lift a concrete block gate if the the concrete weighs 160 lb/ft3. The block is 3' in diameter and 1' thick. It is in a tank of fresh water 15 ft down. the specific weight of the fresh water...

I'm in first-year physics classes and we just wrapped up our solitary chapter on fluid mechanics, which covered the very basics (pressure, Archimedes' Principle, and Bernoulli's equation). I find this more interesting that the classical mechanics we've been doing up till now, so I was wondering...

Homework Statement A long water trough of triangular cross section is formed from two planks as is show in Fig P3.66. A gap of 0.1 in. remains at the junction of the two planks. If the water depth initially was 2 ft, how long a time does it take for the water depth to reduce to 1 ft...

Continuum approximation of fluid mechanics (& relativistic fluids) I have a few 'foundational' questions on fluid mechanics which I haven't been able to find quick answers to, any help would be appreciated. At the start of any course on fluids, one is told of the continuum hypothesis...

Hollow spherical ball with inner and outer radius R and r respectfully is made of a material with density 1. The ball is swimming in a liquid with density 2. How much should be the density of the substance that will fill the hollow ball so that it can float? help pls

Homework Statement Calculate the density in lbm/ft3 with the given formula: ρ=p/RT where p=35 psi, R=1716 ft-lbf/slug-°R, and T=100°F. We have access to a table with basically any unit conversion we would need. The Attempt at a Solution 100°F=37.78°C=310.9278K (35 lb/in2)(144 in2/1...

A metal cube is placed in an empty vessel. When water is filled in the vessel so that the cube is completely immersed in the water, the force on the bottom of the vessel in contact with the cube : Ans: Will remain the same. But how? Won't the force exerted in the second case,i.e when the...

A metal cube is placed in an empty vessel. When water is filled in the vessel so that the cube is completely immersed in the water, the force on the bottom of the vessel in contact with the cube : Ans: Will remain the same. But how? Won't object exert an extra force which will be...

Hi Recently performed a very basic fluid mechanics experiment with water flowing at different speeds through a Venturi Rig. Most of it went as expected, total head stayed roughly the same throughout but slightly decreased from flow loss due to resistant forces. However, at certain random...

Homework Statement Calculate the pressure drag cofficient for a cylinder using the trapezoidal and simpson's rule (assume the flow is the same on both sides of the cylinder). Angle (deg) Cp 0 1 30 0.274 60 -1.565 90...

Homework Statement In a very large closed tank, the absolute pressure of the air above the water is 6.01x10^5 Pa. The water leaves the bottom of the tank through a nozzle that is directed straight upward. The opening of the nozzle is 4.00m below the surface of the water. a) Find the speed at...

Homework Statement The pipe shown has a 180° horizontal bend in it as shown, and D is 20 cm. The discharge of water (ρ = 1000 kg/m3)in the pipe and bend is 0.30 m3/s, and the pressure in the pipe and bend is 100 kPa gage. If the bend volume is 0.10 m3 and the bend itself weighs 500 N...

Hello! I'm a biomedical engineer student and I'm working on a project about the fluid dynamics in artificial hearts. What I want is to compare the fluid dynamics in real hearts and artificial ones, have a general idea on what problems can arise when trying to produce an artificial heart...

Homework Statement A large barge of overall width 4m to be used at sea has a uniform empty weight per meter length of M=6327.19kg/m (length is into the page). This empty weight is uniformly distributed along the length of the barge. The center of gravity of the empty barge is at position G...

This one is actually for a lab assignment. In the experiment you shoot a jet of water upward vertically at a variety of targets with different geometries (a flat plate, various cups). The target is suspended from a rod, and on top of the rod is a cup where you can add weights, held up by a...

Homework Statement I need to find the net force acting on a flat squared roof with area A while the wind is blowing outside at some velocity, v_1. Homework Equations Bernoulli's Equation: P_1+\frac{1}{2}\rho v_1^2+\rho gy_1= P_2+\frac{1}{2}\rho v_2^2+\rho gy_2 The Attempt at a...

We are using Fluid Mechanics by Young and Munson. It is a good book but I want to get another one for more example problems. What is a good textbook for introductory Fluid Mechanics? I am a civil engineering student. Thanks

Here is the problem i am trying to solve; A power-law fluid has a density of 1075 kg/m3. It is pumped at a rate of 2500 kg/hour through a pipe of internal diameter 25 mm.The flow is laminar and the power law constants are K2 = 3 Pa.s^n and n = 0.5. Estimate the pressure drop over a 10 m...

Homework Statement [PLAIN]http://img30.imageshack.us/img30/6918/screenshot20110828at111.png Homework Equations P_base= rho * h * g = 1800 kg/m^3 * h * 9.81 m/s^2 = 17658 * h kg/(m^2 s^2) F_h= .5 * h * P_base = 10594.8 * h^2 kg/(m^2 s^2)The Attempt at a Solution I am trying to find the force...

Hi guys. I have a question on sonic pressure wave behavior in pipes. When a pressure wave traversing down a pipe encounters a change in cross-section, namely, a convergence say like that of an expansion chamber, a negative pressure wave is reflected back in the opposite direction. My...

Hi friends - I'm at a lost on this particular problem which reads: a manometer consists of a U-tube, 7mm internal diameter, with vertical limbs with an enlarged upper end of 44mm diameter. the left-hand limb and the bottom of the tube are filled with water and the top of the right hand limb...

I'm a Mechanical Engineering major and am starting Fluid Mechanics this semester. My professor suggested Fox's book, as he's going to take most problems from that book, though I've heard this book is really weak and I would like to buy something that I could dig further into the subject...

I don't understand why stream tubes exist. Stream tube is defined here: http://www.princeton.edu/~asmits/Bicycle_web/streamline.html Why can't you have a stream line starting at a point going one way, and then the stream line at the neighboring point going some orthogonal direction, and thus...

Hi! Im a student in chemical engineering and I would like some recommendation for a fluid mechanics book, I've been using Bird's Transport Phenomena but it seems to be a bit difficult to follow it, as it skips a lot of steps.

Hey guys, I'm trying to learn fluid mechanics while at an internship and i just have a quick question. Let's say i have a fluid flowing down and incline plane with a quadratic velocity profile. Which direction does the shear stress (tau) act? I know the formula for shear stress is tau =...

Ethanol of density 791 kgm-3 flows smoothly through a horizontal pipe that tapers in cross-sectional area from A1= 1.20 x 10-3 m2 to A2=A1/2. The pressure difference between the wide and narrow sections of the pipe is 4120 Pa. What is the volume flow rate of the ethanol? (Ans.: 2.24 x 10-3...

Homework Statement A model spillway has a flow of 100 L/s per m of width. What is the actual flow for the prototype spillway if the model scale is 1:20? Homework Equations qr = qp/qm The Attempt at a Solution My attempt; qm = 100 L/s per m = 0.1 m^3/s per m Using the...

A uniform film of oil 0.13 mm thick separates two circular discs, each 150 mm diameter and mounted coaxially. Find the torque required to rotate one disc relative to the other at a steady speed of 400 rev/min if the oil has a viscosity of 0.14 Pa.s. (Ignore edge effects at the rim of the...

Homework Statement A helium filled balloon is tied to a 2 m long uniform string of mass 0.05 kg.The balloon is spherical with a radius of 0.4 m. When released it lifts a length h of the string off of the ground. Find the length h given that the balloon has a mass of 0.25 kg. Homework...

If an object like a sphere is submerged in a fluid and held in place by a rope, does the pressure are the top and the bottom of the sphere have anything to do with the weight/density/geometery of the sphere? or is it simply a case of using the hydrostatic equation for the pressure at the top and...

Hi, I am planning to do this as a demo in my fluid mechanics class. I've used glycerine as corn syrup isn't available. It seems to be transparent and viscous enough. Can anyone please suggest a dye? The video seems to be using coloured corn syrup for flow visualization. How can I...

Fluid mechanics and torque... Homework Statement A square gate of size 1m*1m is hinged at its mid point. A fliud of density rho fills the space to the left of the gate. A force F is applied at the bottom of the gate towards right. Find value of F such that the gate is stationary...

Homework Statement The problem involves fluid flow through a 180 degree bend in a pipe. I am trying to find out the force applied on the flanges connecting the bend to straight pieces of pipe. I am given information on the diameter of the pipe, the length of the pipe, weight flow rate, and...

to construct a barometer,a tube of length 1m is filled completely with mercury and is inverted in a mercury cup.the barometer reading on a particular day is 76cm.suppose a 1m tube is filled with mercury upto 76cm and then closed by a cork.It is inverted in a mercury cup and the cork is...

So I'm most likely studying abroad next semester and taking a Fluid Mechanics course. At my home university, the pre-reqs are multivariable calc, diff eq, statics and dynamics, and classical thermodynamics. Abroad, all I need are multivariable and diff eq. But I'm worried that I might be at a...

My question pertains to the following article: http://tinyurl.com/4uw9h2a I have attached the relevant section to this post. My question is whether Godin's assertion is correct or not - namely the sentence "Such a development ... additional terms" and the last sentence in the attachment...

Homework Statement A tube of radius 'R' and height 'H' (placed vertically), is filled with a fluid till a height 'h' (<H). Now it is rotated with an angular velocity 'w' about the central axis. Prove that the shape of the free surface is parabolic. Homework Equations The Attempt at...

1. A 45 US gallon drum full of water is stored at 4oC. The water temperature is slowly raised to 50oC. What is the change in volume of water over this temperature range as an absolute amount (in Litres) and as a % of the total?

Hello How would you calculate the total force (due to air pressure) on the top face of a prism, which is partially immersed in water? The top face is horizontal. What formula do you use? Thank you.