What is Fluid dynamics: Definition and 631 Discussions
In physics and engineering, fluid dynamics is a subdiscipline of fluid mechanics that describes the flow of fluids—liquids and gases. It has several subdisciplines, including aerodynamics (the study of air and other gases in motion) and hydrodynamics (the study of liquids in motion). Fluid dynamics has a wide range of applications, including calculating forces and moments on aircraft, determining the mass flow rate of petroleum through pipelines, predicting weather patterns, understanding nebulae in interstellar space and modelling fission weapon detonation.
Fluid dynamics offers a systematic structure—which underlies these practical disciplines—that embraces empirical and semi-empirical laws derived from flow measurement and used to solve practical problems. The solution to a fluid dynamics problem typically involves the calculation of various properties of the fluid, such as flow velocity, pressure, density, and temperature, as functions of space and time.
Before the twentieth century, hydrodynamics was synonymous with fluid dynamics. This is still reflected in names of some fluid dynamics topics, like magnetohydrodynamics and hydrodynamic stability, both of which can also be applied to gases.
Hi all,
I have just completed my undergraduate studies in Mathematics from a UK university (specialising the Mathematical Physics and Fluid Dynamics) and will be continuing on a Masters programme in Applied Mathematics come fall. For my Masters, I would like to do something on CFD but the...
I've recently read a paper which suggested some properties of vortex's, which I could not confirm in my elementary physics textbooks or during a quick google search.
I hope to find some evidence that:
All vortex phenomena are actually composed of two vortex's:
1 - An outer vortex which...
I am trying to find the total head loss of an air passageway system but I have not taken a fluids class. I have been trying to teach myself the equations and principles but it tends to be very confusing without guidance. So here is my question:
I have a wheel-end knuckle with an air passage...
Hi,
I've decided I want to pursue a career in CFD (Computational Fluid Dynamics) and I think the best career option for me would be be to take up 'teaching' in my area of interest (since I'm not sure how well I'd be able to do in hard-core research activities) . However, I'm completely unaware...
Homework Statement
A circular jet of water of radius r1 is propelled vertically downwards and hits
a circular plate of radius r2 (> r1 ) so that the centre of the jet is incident onto the
centre of the plate. The velocity of the jet as it hits the plate is v and is normal to
the plate...
Homework Statement
Consider the cross section of a sluice gate, which is a device for controlling the flow of water in channels. Determine the force on the gate per unit width of the gate.
Hint: think of each line as a surface, with the length given above, and 1 foot of depth in the direction...
Homework Statement
A pipe tapers from a diameter of 0.5 m at the inlet to a diameter of 0.25 m at the outlet, and turns by an angle of 45 degrees. The gauge pressure at the inlet and the outlet are 40000 N/m2 and 23000 N/m2, respectively. The pipe carries oil, with a density of 850 kg/m3, at a...
Dear all
I have 1 simple question. If the solution of Navier Stokes equation exists, its limits for infimum length, time and velocity would be the Kolmogorov Microscale equations, am I correct?
Thanks,
Robert
Suppose an inviscid, incompressible fluid is rotating uniformly with angular velocity \Omega. Take Cartesian axes fixed in a frame rotating with that angular velocity.
Show that the evolution of a SMALL velocity field, u_1 = (u_1, v_1, w_1), relative to the rotating axes and starting from rest...
Homework Statement
Consider a water pipe that tapers down from a diameter d_A = 5.0 cm at end A to a diameter d_B = 2.5 cm at end B. At each end a vertical pipe that is open to the air at the top is attached to the pipe. Assume that water flows through the pipe at high enough pressure that the...
Homework Statement
Show that, for an inviscid fluid, we have
\frac{D}{Dt}\bigg{(}\frac{\mathbf{\omega}}{\rho}\bigg{)} = \bigg{(}\frac{\mathbf{\omega}}{\rho}\cdot \nabla \bigg{)}\mathbf{u} - \frac{1}{\rho}\nabla\bigg{(}\frac{1}{\rho}\bigg{)} \times \nabla p
Homework Equations
Euler's...
Homework Statement
An ideal fluid is rotating under gravity g with constant angular velocicy \Omega, so that relative to the fixed Cartesian axes \mathbf{u} = (-\Omega y, \Omega x, 0). We wish to find the surfaces of constant pressure, and hence the surface of a uniformly rotating bucket of...
I am finding the recommended textbook for fluid dynamics really dull. It's slowly going from one formula to another with nothing interesting or any attempt at all to keep you awake...
I'm strong with regard to maths, so are there any books that might make the subject more interesting?
Even...
Help me, please / Advanced Fluid dynamics Problems
Homework Statement
Evaluate the radial component of the inertia term (u dot Del)u in cylindrical
coordinates using the following identities:
x=RcosΘ
y=RsinΘ
uEx+vEy = UrEr+UΘEΘ
and any other vector identities from Appendix A as...
Firstly, the whole question is below, for now I need help on parts of the question- I've included it all for clarity and just in case I have further problems.
An equilibrium ring of isothermal fluid orbits a star at radius R. In the plane of the ring, mechanical equilibrium results from a...
Problem Statement
A 50cm by 30cm by 20cm block weighing 150N is to be moved at a constant velocity of .8 m/s on an inclined surface with a friction coefficient of 0.27. (a) Determine the force f that needs to be applied in the horizontal direction. (b) if a .4mm thick oil film with a dynamic...
Homework Statement
A very large open water tank has a 50 cm diameter output pipe connected 10 m above the water main which is 6 cm in diameter. If the gauge pressure in the water main reads 9.8 E4 Pa what is the speed at which the water is supplied?
Homework Equations
I know you need...
Homework Statement
A very large open water tank has a 50 cm diameter output pipe connected 10 m above the water main which is 6 cm in diameter. If the gauge pressure in the water main reads 9.8 E4 Pa what is the speed at whic the water is supplied?
Homework Equations
Bernoulli's...
Homework Statement
A bomb located 3 meters below the ground needs a certain pressure in order to pump the water through the pipe (connecting the ground to the bomb) and 12 meters above the ground. The radius of the pipe is 0.01 meters and the radius of the 'mouthpiece' of the tube in the...
Homework Statement
A fresh water pond that is 15.0 m deep is contained on one side by a cliff. The water has eroded a nearly horizontal "tube" through a bed of limestone, which allows the water to emerge on the other side of the cliff. If the "tube" has a diameter of 4.26 cm, and is located...
If this isn't the right forum, please move me to a better one.
Assume that the output of a mountain spring is diverted to a reservoir about 200 feet below the spring through the following airtight system:
A two inch pipe leads from the spring to a 40-gallon drum that lies on its side a few...
Fluid Dynamics - urgent
Homework Statement
A cylinder of radius a is placed in a uniform stream of speed U. Fluid is blown steadily outwards across the surface of the cylinder so that the normal component of velocity on the surface is V.
a, find the velocity potential for the flow
b, show...
So basically I'm considering applying to physics or applied physics grad programs. But I'm also considering doing CFD as a career. I was hoping there was a way I could see them both in a grad program, but I haven't seen any physics grad programs with CFD as a research area by itself. Rather, I...
Fluid Dynamics - Multiple Pipe System Need Help Please!
There are 2 pumps at 2 locations with pipes (12") running from each of the pumps that are to both tied into 1 pipe (16"). In order to tie the 2 pipes into the one pipe there will be a 90 and a y fitting. The 16" pipe will then continue...
Homework Statement
An iceberg is floating on sea water such that only 10% of its volume is above the water level. What is the density of sea water expressed in terms of the density of ice.
Homework Equations
\frac{Vf}{Vi} = \frac{\rho}{\rho}
\rhof = density of sea water
\rhoi =...
Hello Physics Forums,
I am going into 2nd year physics and am thinking about taking some additional math courses. My interests lay with ships and the ocean. What math courses would be most useful for research in fluid dynamics and interactions with structures?
Thanks,
Adam
Q) " Estimate the average acceleration of water as it travels through the nozzle on your garden hose. List all the assumptions and show calculations. "
Plz help...ny body before i come a dead body ! :mad:
Homework Statement
A fire-hose must be able to shoot water to the top of a building 35.0 m tall when aimed straight up. Water enters this hose at a steady rate of 0.500 m³.s¯¹ and shoots out of a round nozzle.
(a) What is the maximum diameter that this nozzle can have? (4 marks)
(b)...
I'm no good with fluid dynamics. I really am willing to improve can someone point me to what equation I should use for this question. I assume its bernoullis equation? I've drawn a diagram of how I see the pipe.
To make things worse I haven't done fluids in quite a while.
Homework...
i want to master computational fluid dynamics,i do not have that as a subject
in my university.so if i do it on my own,please give an idea about the best books for it?
Let's say I want to install a 55 gallon drum on the ground to collect rain water as it runs off the roof. What if for some strange reason I wanted to run a hose from a spigot in the bottom of the drum back up to water the plants on the roof deck (I'm looking into green roofs). Could we just...
1.Water flows in a horizontal pipe with variable radius and which produces no drag. At one point in the pipe where the radius is 5.0cm, the flow is noted as .75 m/s at a pressure of 250 N/m^2. a) What is the velocity at a point in the pipe where the pressure is 200 N/m^2? b) What is the radius...
Sorry I'm not sure where to post this as there is no explicit fluid dynamics forum - i just did a search and noticed majority of posts fell into the "mechanical engineering" forum for some reason. Sorry about that.
Today my professor has told the class that by next week we have to code in...
Homework Statement
Air flows from a hole of diamter .03 m in a flat plate as shown in the figure. A circular disk of diameter D = .15 m is placed a distance h from the lower plate. The pressure in the tank is maintained at 1 kPa. Determine the flowrate as a function of h, ignoring viscous...
Hi everyone,
I am new to the forum, so please instruct me if I commit any posting faux pas in my first post.
Here is my dilemma: I have an oxygen concentrator that outputs .5-5 liters per minute of 95% concentrated oxygen at 5 - 7 PSI. This is just fine for medical use, but I am trying to...
Homework Statement
A hypodermic syringe contains a medicine with the density of water. The barrel of the syringe has a cross-sectional area of 2.5*10^-5 m^2. In the absense of a force on the plunger, making the medicine squirt from the needle. If the syringe is horizontal and the pressure...
I am having a tank at the bottom of which a pump suction line is connected..
there is another parralel line to that bottom line which is coming from another tank and open to atmospheric pressure.
Please note that this second pipe is connected to the bottom pipe; not to the first tank...
(a) Is it true that if the mass flow rate of a gas is low, say 2g/s (grams per second), the friction losses and other losses in the piping will be negligible?
(b) If it is true that losses in the piping are negligible, is it the Euler's dimensionless number that we can use to prove this...
Homework Statement
okay, so the lab that we did is called fluid dynamics. where we open a hole but before we are supposed to record h1 before the hole is open and also measure the height of the hole. h1 is higher than h. so every 30 seconds, we have to record h2, h3 ,h4 corresonding with...
Homework Statement
The horizontal constricted pipe illustrated in
lee (vl3765) – UTHW#34-Dluid Dynamics1 – hamaguchi – (32001) 3
the figure (a Venturi tube), can be used to
measure flow velocities in an incompressible
fluid.
The ratio for the cross section areas of the
tube is A2/A1 =...
just wanted to say hi first as this is my first post.
I will explain the story...
There is an ongowing debate within the Kitesurfing world regarding the aerodynamics of LEI (leading edge inflateable) kites and Foil (like RAM aim parachutes) kites.
LEI Kites:
They have large inflateable...
Can fluid dynamics be applied to a particle moving through a Higgs field?
Like is there a wake, or even a slipstream in which a trailing particle might be affected less by the Higgs field or not at all?
Homework Statement
A tank at sea level with fresh water measuring 36"x19"x30" contains a one inch bed of sand. The sand particles are .21 mm in size and have a specific density of 2.6.
The water in the tank recirculates at a rate of 1,000 gph. There is a one inch return at the surface of...
How much force is necessary to lift a ring, diameter 20mm, made of fine wire, and placed on the surface of water at 20 degrees celsius?
All the equations from the chapter:
Shearing stress = F/A = Viscosity*(velocity parallel/h)
Kinematic Viscosity = viscosity/density
Change in pressure =...
"If you put your arm in a stream flowing at U metres per second, how far can water rise up it?"
Not really sure if what I'm doing is right. Presumably it depends on the angle of your arm in the water. If we let the speed of the water at your arm be V, we get, by Bernoulli, taking the height...
Homework Statement
An average person has about 5 litres of blood in
their body. The heart circulates all this blood
around the body in only about 1 minute. Find the
time averaged volumetric flow rate Q of the aorta,
which is a pipe of inner diameter 2.2 cm. Find
the time and space...
http://home.cc.umanitoba.ca/~loly/102-dec_word.pdf
The above is a link to the problem - Question #3.
Homework Statement
A glass tube has several different cross-sectional areas with the values indicated in the figure. A piston at the left end of the tube exerts pressure so that the mercury...
Before I describe the problem, I would like to apologize for my lack of comprehension
of this subject. It is the first semester of Physics, but the end, and has become quite
complicated.
Homework Statement
There is a 2.0 L soda bottle used, with a hole a certain height (hhole) from
the...
Homework Statement
Consider the Rayleigh problem, but allow the plate velocity to be a function of time, V(t). By differentiation show that the shear stress, tau = du/dy*absolute viscosity, obeys the same diffusion equation that the velocity does. Suppose that the plate is moved in such a way...
Hey guys,
I have the following (non-homework) problem:
I am simulating a collection of normally distributed non-interacting stars falling into a much larger galactic potential from some radial distance and some initial velocity and watching them slosh around in this potential. Currently i...