What is Fluid mechanics: Definition and 755 Discussions
Fluid mechanics is the branch of physics concerned with the mechanics of fluids (liquids, gases, and plasmas) and the forces on them.:3
It has applications in a wide range of disciplines, including mechanical, civil, chemical and biomedical engineering, geophysics, oceanography, meteorology, astrophysics, and biology.
It can be divided into fluid statics, the study of fluids at rest; and fluid dynamics, the study of the effect of forces on fluid motion.:3
It is a branch of continuum mechanics, a subject which models matter without using the information that it is made out of atoms; that is, it models matter from a macroscopic viewpoint rather than from microscopic. Fluid mechanics, especially fluid dynamics, is an active field of research, typically mathematically complex. Many problems are partly or wholly unsolved and are best addressed by numerical methods, typically using computers. A modern discipline, called computational fluid dynamics (CFD), is devoted to this approach. Particle image velocimetry, an experimental method for visualizing and analyzing fluid flow, also takes advantage of the highly visual nature of fluid flow.
Hey Guys,
I am supposed to take Fluid Mechanics in Fall 2013. The course has lots of prerequisites and I have taken them all.
One of the prerequisites is Dynamics. In Dynamics I was taught how to analyze objects in motion using Newton's Second Law of motion, Work and Energy method and...
An unsteady fluid flow has velocity field q= - 1/2 sin t ( xe^-y, e^-y).
Show the flow is incompressible and find a stream function.
Find the path of the fluid particle which is at (1,0) at t=0.
I only know it has six faces and the sum of all six terms has to be zero in order to show the...
It appears to me that a typical physics curriculum only touches upon topics from fluid mechanics very briefly in the introductory level physics. However, I imagine that the material there is very interesting and potentially relevant (plasma physics, etc).
If I wanted to get a deeper...
A television transmitting antenna is placed on top of a mast which is 30m high and 300mm in diameter. The mast is on top of a tall building. The wind blows at 35m/s and at normal atmospheric pressure (1.225kg/m^3). If the drag coefficient for the mast is 0.2. calculate:
(i) the total drag...
Homework Statement
the probem is from the book:
Fundamental mechanics of fluids by I.G. Currie
is from the chapter 4 ( 2 dimentianal potential flows )
is the problem 4.4:
. Consider a source of strength m located at z = −b , a source of strength m
located at z=- a^2 / b , a sink of...
Hi, I am a first year studying mechanical engineering and I am having trouble understanding bernoulli equation. This is the first question in the tutorial and I can't seem to get the right answer.
Water flows through the pipe contraction shown
in the figure below. For the given 0.2 m...
I'll be starting a graduate program in a computational science department in September. My research will be in the field of Fluid Mechanics. However, I don't come from an engineering background. My undergraduate degree is in Applied Mathematics where I studied ODEs, PDEs, Calculus, Algebra...
Homework Statement
A tank consists of two chambers, one open to the atmosphere and another closed and filled with a gas. The two chambers are connected by a sluice opening. What is the pressure in the gas, in gauge and absolute terms if the barometric pressure = 742 mm Hg. Difference in height...
Homework Statement
The Attempt at a Solution
I am interested in why my method is flawed:
Alright I know how to do this problem. Essentially you solve mass flow rate = rho * double integral of u dA. HOWEVER, I decided to do this differently. I know that I can solve for the average u from...
Hi all,
I am stuck on a problem, and it's been a while since I took fluid dynamics. I have a cylindrical tank of know capacity with an inlet, where a vent is attached, and an outlet, the fluid gets sucked. The tank has fluid in there with known volume and density. If I know the usage rate of...
Hi,
I've done a search and I know that other people have askled for a good textbook for fluid mechanics for a 1st year Mech Eng student however, I'd like to find one with a lot of worked example ploblems.
I'm finding my course notes are too far a jump from the simple examples our lecturer...
Im confused with the sign convention... From my notes I have that for
mass flow rate: Entering is -m and leaving is +m
momentum : Entering (-m)(+v) and leaving is (+m)(-v)
Example: for a rectangular control volume, let's say, left side is point 1 and right side is poinit 2...
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...
Homework Statement
Use the continuity and momentum conservation equations for a single species to construct the following "convective derivative" equation for the fluid velocity:
\frac{\partial\vec{v}}{\partial t}+\vec{v}\cdot\nabla\vec{v}=\vec{g}-\frac{1}{\rho}\nabla p...
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...
the probem is from the book:
Fundamental mechanics of fluids by I.G. Currie
is from the chapter 4 ( 2 dimentianal potential flows )
is the problem 4.4:
. Consider a source of strength m located at z = −b , a source of strength m
located at z=- a^2 / b , a sink of...
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...
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...
Hey! (First post)
We're conducting an experiment as a part of a couple of problem sets in preperation for the IYPT, and we're a little stuck in terms of the research we need to have to solve the problem. Basically, (I'm not going to copy paste the question in here, I'd be cheating) We've...
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...
Homework Statement
Develop the pump head curve.
Homework Equations
The Attempt at a Solution
Top branch: ## \Delta h=2(a-b(\frac{Q}{2})^2) ##
Bot branch: ## \Delta h=a-b(\frac{Q}{2})^2 ##
Combining them is where I'm having trouble; I don't understand what to do with the a term. Add...
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...