Fluids Definition and 522 Threads

Hey guys, I am studying in heriot watt university Dubai. I would like to be a Fluids expert. I have been doing well in my course-works and my professor usually helps me around to get a few extra info. However recently due to a tight schedule he is unable to help me out. I have managed to...

Hi I am working in an application where we pump a fluid in a water -filled tube, where the second fluid has a viscosity of 3-4 times the viscosity of water. We have laminar flow (Re around 20). If the fluids were 100% compatible (e.g. colored water vs clear water) I have determined that...

Hi, I am trying to do a cross flow analysis in FLUENT. Air and water in a cross flow heat exchanger. The fluids do not come in contact. I have modeled and meshed the geometry in GAMBIT. Could someone pls help me with the steps in FLUENT as to how to assign different fluid properties for...

I'm stumped on a HW question that I just can't seem to proceed on. Homework Statement An incompressible ( rho = constant ) flow in 2 dimensions [x = (x,z)], with F = (0,-g), satisfies Euler's equation. For this flow, the velocity is u = (u0,w(x)), where u0 is a constant, with w = 0 on x...

Homework Statement A boat floating in fresh water displaces water weighing 37.3 kN. What is the difference between the volume of fresh water displaced and the volume of salt water displaced (Vfresh - Vsalt)? F(bu) = 37.3E3 kg/m^3 (rho)fresh water = .998E3 kg/m^3? (rho)salt water =...

Homework Statement Very small particles moving in fluids are known to experience a drag force proportional to speed. Consider a particle of net weight W dropped in a fluid. The particle experiences a drag force, Fd = kV, where V is the particle speed. Determine the time required for the...

Homework Statement In an ideal fluid, the pipe length is doubled, while radius is decreased by factor 2 what will have to the velocity and volume that is flowing? Homework Equations Q=Av = pi*r^2*v The Attempt at a Solution From this the volume that will pass, in ideal fluid cases...

An open tank has a horizontal bottom. It is divided into two parts by a vertical gate. The gate is rectangular, 3m high and it is hinged at its top. Water of density p,=1000kg/m3 in one part of the tank is acting on one side of the gate, and oil of density p, in the other part of the tank is...

Hi - I'm having trouble with the bouyancy force. I understand that in static equilibrium a force from below a submerged object (not resting on the floor of a container but in the liquid) equals the overlying liquid plus the weight of the object. So that the bouyancy force is the difference of...

Okay, so I'm stuck on the last part of the problem : A hydraulic lift has two connected pistons with cross-sectional areas 15 cm2 and 430 cm2. It is filled with oil of density 620 kg/m3. -------------------------------------------------------------------------------- a) What mass must...

When I have an ionized fluid (plasma) and I describe it in a continuum approach I can use the MHD equations (the continuity equation, the equation of motion, the induction equation and the energy equation). However; I am modeling a certain model of a sunspot and there is also an unionized...

Homework Statement Hi, I'm trying to follow the proof for the statement \nabla . u = 0 I'm basing it off this paper: http://delivery.acm.org/10.1145/1190000/1185730/p1-bridson.pdf?key1=1185730&key2=4151929021&coll=GUIDE&dl=GUIDE&CFID=25582973&CFTOKEN=82107744 (page 7, 8) In...

I understand that in an ideal fluid, when the cross-sectional area of the pipe is increased, the pressure that the fluid exerts on the walls of the pipe also increases. Also, when the cross-sectional area of the pipe is decreased, the pressure that the fluid exerts on the walls of the pipe...

[SOLVED] need help with fluids and pressure problem Homework Statement The L-shaped tank shown below is filled with water and is open at the top. (a) If d = 4.0 m, what is the force on face A due to the water? N (up) (b) What is the force on face B due to the water? N (right)...

Homework Statement THe human lungs can operate w a pressure differential of abt 1/20 of an atmosphere. If a diver uses a snorkle for breathing, about how far below the water level can they swim? Homework Equations P=P(i) + pgh where p is ro, density. The Attempt at a Solution...

Homework Statement A simple U-tube that is open on both ends is partially filled with a liquid of density (491 kg/m^3). Water is then poured into one arm of the tube, forming a column height of (8.2 cm). The density of the heavy liquid is (1000 kg/m^3). What's the difference , h, in the...

Hello all, I have a very basic question about fluids. Here it is. There are two containers, one has alcohol in it and the other has oil. A steel ball is held down inside of each. A scale will weigh the steel ball as it is held down in the alcohol and then in the oil. Will the ball be...

1. A man falls into a tank at 40 degrees C. His body temperature is 98.6 degrees Fahrenheit. I want to ask if the man will freeze to death, but I don't know at what temperature that happens. Can I ask them to figure out what his final body temperature is, if say he doesn't get rescued in 10...

Homework Statement An above-ground backyard swimming pool is shaped like a large hockey puck, with a circular bottom and a vertical wall forming its perimeter. The diameter of the pool is 5.2m and its depth is 1.4m. Find the total outward force exerted on the vertical wall of the pool...

Homework Statement Hi guys Please take a look at the second question in 10.20 (the question with the diff. equation)...

1. The time required to fill a bucket with water from a certain garden hose is 30.0 s. If you cover part of the hose's nozzle with your thumb so that the speed of the water leaving the nozzle doubles, how long does it take to fill the bucket? 2. Homework Equations : None required. I hope...

Homework Statement A solid cylinder 350mm in diametre and of total length 750mm floats upright in fresh water to a depth of 500mm determine (a) the mass of the cylinder.(b)the density of the material in the cylinder. Homework Equations mg=pgha The Attempt at a Solution area= lxd...

First, let me introduce myself. I am new to these forums, but not new to sharing ideas that cause argument. If you think anything I say is wrong, please speak up. The reason I joined was because of this outrageous 2+ year old thread: https://www.physicsforums.com/showthread.php?t=70227 The...

[SOLVED] Fluids and Forces Hi, I'm new to this site, so I'm not sure if this is the right place to post. I found a year-old entry with the same question that I'm having trouble with, found here: https://www.physicsforums.com/showthread.php?t=153538" For Part a, I followed the same method...

Homework Statement Using Archimedes' Principle and the diagram shown: (diagram is a "mass" of something in a liquid with an immersed portion (Vb) and an Un-immersed portion (Va)). A. prove that if an object is floating in a liquid, the fraction of the object's total volume that is...

Fluids at rest problem help! Homework Statement How much force does it take to hold 0.5 m^3 of medium density (specific gravity = 0.77) wood under water? The Attempt at a Solution density of wood is 770 kg/m^3. Fb is the force of buoyancy that pushes the wood up. F-Fb = mg...

Hi, I am having some trouble with a couple problems from an AP Physics worksheet. I don't really think that they are actually that hard overall but I'm justhaving a hard time tryng to figure out where to start. Here they are: A 90,000 kg structure is built on stilts on the surface of Saturns...

Homework Statement A cylindrical can of height h and base area A is immersed in water to a depth ho and left to sink down. A small hole of area 'a' exists at the bottom of the base of the can. Determine how quickly the can sinks. http://img80.imageshack.us/my.php?image=fluids1wb7.jpg...

heheh...I need some help understanding something. If there was an object, such as a sphere, in water, gravity would be pushing it downwards, while a resistive force R = -bv would be pushing it upward (b as a constant). that would imply that the net Force Fy would be Fy = mg - bv = ma =...

Homework Statement A small sphere 0.75 times as dense as water is dropped from a height of 11 m above the surface of a smooth lake. Determine the maximum depth to which the sphere will sink. Neglect any energy transferred to the water during impact and sinking. for clarity's sake, I'm...

A cylindrical container 1.2 m tall contains mercury to a certain depth, d. The rest of the cylinder is filled with water. If the pressure at the bottom of the cylinder is 1.9 atm, what is the depth d? Does anyone have any ideas on how to approach this problem, better yet,solve it!?

[SOLVED] i need help with a static fluids question Homework Statement A block of wood of 1.8 kg mass floats on water with 64% of its volume submerged. A lead block is placed on the wood and the wood is then fully submerged. Find the mass of the lead block. Homework Equations Fb =...

Homework Statement Heated air at 1 atmosphere and 35 deg. Celsius is to be transported in a 150 meter long circular plastic duct (smooth) at a rate of 0.35 cubic meters/sec. If the head loss in the pipe is not to exceed 20 meters, determine the minimum diameter of the duct. Homework...

could not solve this exam problem completely please help: Variations in surface tension can cause a flow in a liquid.One of the chief causes for variation of surface tension is temperature.Consider a thin film of liquid on a flat surface.The liquid film also has a free surface where the...

Homework Statement A brick weighs 15.0 N and is resting on the ground. Its dimensions are 0.203 m 0.0890 m 0.0570 m. A number of the bricks are then stacked on top of this one. What is the smallest number of whole bricks (including the one on the ground) that could be used, so that their...

I have solved this problem but am not sure where I'm going wrong here... Suppose you pour water into a container until it reaches a depth of 20cm . Next, you carefully pour in a 9.7cm thickness of olive oil so that it floats on top of the water. What's the pressure at the bottom of the...

Homework Statement In scuba diving, a regulator is used so that the pressure of the air the diver breathes is close to that of the ambient water. A reckless swimmer decides to use a hose sticking out of the surface to breathe underwater while diving in a lake. When the air pressure in the lungs...

Homework Statement Water runs into a fountain, filling all the pipes, at a steady rate of 7.52×10−2 m^3/s How fast will it shoot out of a hole 4.53cm in diameter? Homework Equations A1V1 = A2V2 The Attempt at a Solution A1V1 = 7.52x10-2 m^3/s = A2V2 Divide by A2, which...

Homework Statement The diameter of a certain artery has decreased by 22% due to arteriosclerosis. (a) If the same amount of blood flows through it per unit time as when it was unobstructed, by what percentage has the blood pressure difference between its ends increased? (b) If...

Homework Statement Water (n = 1.00 10-3 Pa·s) is flowing through a horizontal pipe with a volume flow rate of 0.029 m3/s. As the drawing shows, there are two vertical tubes that project from the pipe. From the data in the drawing, find the radius of the horizontal pipe. Homework...

Homework Statement A flat plate viscometer consists of a disc of diameter 50mm rotating at 300rpm in close proximity to a fixed horizontal plate. When the gap between the plates is 0.1mm, it is found that the torque required to drive the disc is 0.2Nm. What is the viscosity of the liquid...

Homework Statement Water flows steadily from an open tank. The elevation of point 1 is 10.0 m, and the elevation of points 2 and 3 is 2.00 m. The cross-sectional area at point 2 is 0.0480 m^2; at point 3 it is 0.0160 m^2. The area of the tank is very large compared with the cross-sectional...

Hi, I have nothing to do this summer so I figured I would like to model the heat transfer for different shapes and fluids and compare with experimental values.. :) Anyway I searched on google and found nothing. What are the main problems? For example is it acceptable to assume that the...

Homework Statement a. Given potential flow, find stream function and velocity components. b. Compute pressure along the x-axis and plot it. Homework Equations Psi = 2axy The Attempt at a Solution So, I got the psi from phi (above) but i don't understand how I am to go from...

[b]1. There is a cylinder fitted with a piston, the piston has a mass m1 of 0.50 kg and a radius of 2.50 x 10^-2 m. The top of the piston is open to the atmosphere. The pressure underneath the piston is maintained at a reduced (but constant) value by means of the pump. As shown, a rope of...

1. Which of the following is not a unit of pressure? (Points: 1) atmosphere N / m Pascal mm of mercury Well, I would say it's N/m, but I thought it would not hurt to check. 2. When atmospheric pressure increases, what would hapen to the absolute presure at...

Homework Statement In a sample of seawater taken from an oil spill, an oil layer 4.0 cm thich floats on 55 cm of water. If the density of the oil is 0.75 x 10^3 kg/m^3, what is the absolute pressure on the bottom of the container. p= 0.75x10^3 kg/m^3 g = 9.8m/s^2 h=.55m p=? pa =...

1. A tube of radius 5 cm is connected to tube of radius 1 cm as shown above. Water is forced through the tube at a rate of 10 liters/min. The pressure in the 5 cm tube is 1×105 Pa. The density of water is 1000 kg/m3. Assume that the water is nonviscous and uncompressible. 2. P=F/A, Q=v1A1...

Super fluids are fascinating. Got this from Wikipedia, but I have also read it at other sites/books.. "Superfluidity is a phase of matter or description of heat capacity, in which, supercondictivity and "unusual" effects are observed when liquids of typically helium-III or hydrogen overcome...

When a stream falls from a fosset it thins out near the bottom. Why is that? This eems to apply to any falling fluid.