Fluid Definition and 1000 Threads

Homework Statement Determine the depth of the flow of channel if the best hydraulic channel is needd for composite channel in figure to convey flow rate of 6.5(m^3/s) , Manning coefficient n on bed slope are 0.015 and 0.0015 respectively . Homework EquationsThe Attempt at a Solution I assume...

Homework Statement This is not so much a homework problem but a question I have on the subject while studying. I have a terrible teacher who is contradicting my textbook constantly and I really want to learn this. Is a pressure field vector or scalar? If given the velocity components, is...

Homework Statement I need to show that a particle suspended on a spinning liquid (which is spinning with constant angular velocity) describes a spiral . (I need to solve this without using Lagrangian-Hamiltonian formalism)Homework Equations [/B] Weight and Bouyant forceThe Attempt at a...

Hello Physics Forums, I have a fluid dynamics problem which appears to challenge some momentum principles. Suppose you have two submarines (like below), identical in shape, but not in mass. One of the submarines has density equal to the fluid, while the other is denser. They move at the same...

This is something I do not know how to explain. Although velocity decreases due to friction with ambient air, momentum should be conserved and, therefore, it entrains mass. What is the reason that momentum should be conserved?

Hi guys.. I've some discussion with my friend. We are teacher. So we must carefully to answer question for student.. there the question is From figure below, p2 and p1 applied on plane's wings. When airplane landing/decrease altitude, which condition must occupied A. P1=P2 and v1=v2 B. P1<P2...

In a fluid moving at constant velocity V, a concentration will undergo diffusion and convection $$U_t=\alpha^2 U_{xx}+VU_x$$ I understand that in this situation you can transform to a moving coordinate system and the convection term will disappear and you can solve for diffusion alone and...

I am graduate student from structural mechanics of solids and need to learn 1 course from fluids and thermal group which includes fluid mechanics or thermodynamics+heat transfer. I am unsure which one would be better to learn, especially which would be helpful in future for solid mechanics. Can...

Hi! I'm looking for a somehow "serious" textbook about fluidmechanics, something like the book by Kundu-Cohen...a book talking about it without by-passing the math involved (tensor analysis) like many books do! Thanks

I did a lot of googling but could not find a satisfying answer to my question, hence a post here. Question: How to solve (or close) the isothermal incompressible Navier-Stokes equations for an isothermal compressible fluid? Situation: We have a compressible fluid, for example a gas. The flow...

I've made a fluid flow simulator, for anyone interested in fluid dynamics. The simulator models some basic flows which I learned on a 2nd year fluid dynamics course. It doesn't include viscosity, density or whatever else (hence for example the flow past a sphere in the simulator is a perfect...

Homework Statement In the notes , it's stated in the first part for non-uniform flow that the gradient of $$S_0$$ , $$S_w$$ and $$i$$ are not the same , But , in the lower part , it's stated in the first part for non-uniform flow that the gradient of $$S_0$$ , $$S_w$$ and $$i$$ are the...

Can someone smarter than I, please express p1 and p2 in terms of f, or v and r? The pump pushes out water at f rate which creates velocity v in the bigger pipe. When the water comes to the restriction velocity increases while flow rate is conserved. Bernouli tells us that the change in...

I should be able to do this, but its been a while and maybe I'm making this more difficult that it should be. Assume you have a cylinder nearly sealed but with an outlet hole at the top. I want to pump a fluid into the canister, pushing the air out of the hole, and time how long it takes. The...

1. Can a fluid which is accelerating down an inclined channel with constant acceleration still satisfy the continuity equation for a constant-density fluid? Since the acceleration will be down the slope, in the streamwise direction, then surely ∇⋅U > 0? 2. Assuming that continuity is satisfied...

I am trying to model fluid flow and losses through a component (e.g., pipe) using REAL GAS properties since 1) I have access to RefProp from NIST, and 2) I am dealing with refrigerants, which are far from ideal. I have seen nowhere an analysis of fluid flow losses (e.g., drag, friction...

Homework Statement A block has dimensions 0.015 x 0.2 x 0.1 meters and weighs 6 Newtons. A 15mm-diameter jet of water is deflected by the block. Find the flow rate needed to tip the block. Homework Equations Mass conservation: ∂/∂t ∫(control volume)ρ d∀ + ∫(control surface) ρv•n dA = 0...

Homework Statement I need to find the pipe diameter or mean velocity. Q= 0.01m^3s Density= 960kg m^3 Viscosity = 0.081 Pa s Max Velocity = 1.8 m s Homework Equations Mean velocity= 4Q/pi.D^2 The Attempt at a Solution I have two unknowns in this equation so I'm unable to find D or Mean...

In an electrical high pressure water motor or pump what is the main cause of energy loss. Originally I was thinking along the lines of 1st heat/electrical losses in motor. 2nd Friction of the water in pipes. 3rd noise. But I'm torn between the first 2 ? Tho

Homework Statement so I have been working on this problem : Diameter1 at wide end: 8cm || V1 = 1.56m/s Diameter2 at narrow end: 3cm || V2 = 11.094m/s Force exerted on plate = 87N Find the manometer reading Picture below: Homework Equations P1+(1/2 ρv1^2)=P2+(1/2 ρv2^2) 1 − 2 = (2 −1)ℎThe...

I have a diagram similar to the following. Water entering the larger end is at 20degreesC. The larger end has a diameter of 8cm and Area 50.26cm2. The small side has a diameter of 3cm and Area 7.0685cm2. The water jet exerts a force of 87N on a flat plate at an unknown distance. Assuming no...

Homework Statement See the photo of the problem in the attachment Homework Equations Bernoulli equation and continuity equation The Attempt at a Solution I don't know from where to begin , i only can get the velocity of fluid when it reaches the hole

Take a U-shaped piece of pipe, standing upwards. Fill the bottom part with liquid and leave the 'prongs' open. Now slam a parcel of liquid into one end at high speed. The other end will experience some momentum exchange and go pushed upwards. Now take the same test case and add some piping...

Hello everyone, First of all I am new here~ Second, I would like to "prove" on COMSOL that soundwaves (sound vibration) can alter/reshape the fluid flow Can someone tell me the physics i should use as well as all the other parameters to make it work? if someone is more experience can they...

When solving for the hydrostatic force on a surface we use the height to the centroid(hc), then when using the point of application we use the y coordinate of the centroid(yc), however shouldn't they be the same since they both start from the top surface and reach down to the object surface on...

Hello, please see attached text below - this concerns ''rigid column theory''. When a valve is closed, the pressure rises at the valve; the pressure rises above the reservoir pressure by ΔP with a height increase ΔH above H. When the valve is opened, this right hand pressure will disappear and...

Homework Statement Flow in a pipe splits into two parallel pipes. All three pipes have same length L, and same friction factor f. Diameter of first pipe is D. The two parallel pipes have diameter D and D/2. All three pipes are on same horizontal level. At the outlet of the two parallel pipes...

A friend is planning to utilize a local stream to create electric power. The source of the stream is a small pond. He plans to have a 5 inch pipe start at/near the bottom of the pond and this pipe will follow the stream approximately 1056 feet to a culvert where he wants to put the generator...

Would it be correct to say the following... CO2 for example can change the surface tension of water from 72 mN m−1 to 57 mN m−1 as its pressure changes from 1 to 11 bar. I'm used to dealing with concentrations, in fact I would like to change bar to volume percent if anyone has a free moment...

Hello Please see attached page from a textbook. Can someone explain why H = 4f.le.vo^2/2d.g and why delta H is given by the expression in the book? Note that the figure it mentions is on the top of the page. I have tried for days here. Thanks

I'm currently struggling slightly with finding some information regarding a vortex. If I have a fluid in a cylindrical container and the fluid is then rotated at a constant speed, the vortex will displace the water and raise it relative to the initial level of the fluid. Is there any formula...

Picture water flowing in a duct. In these kinds of scenarios, the loading exerted by the moving fluid to the solid in the perpendicular direction is often taken as being equal to the pressure of the fluid at the wall. I agree that the above assumption is true for a stationary fluid. For a...

This question is related to a project. I have the mass flow rate, RPM, and all other related information regarding a refrigeration cycle, does anyone have an idea on how can I estimate the total amount of working fluid I need to put into the device? In case this comes up: the device is going...

Hello, I am trying to understand how to apply Bernoulli's equation (which is valid along a single streamline and in the case of zero viscosity) to the situation below. The ideal fluid moves at constant speed along the horizontal pipe. Because the fluid is ideal (zero viscosity), the ideal...

"Liquid immersion provides a way to reduce the physical stress of G forces. Forces applied to fluids are distributed as omnidirectional pressures. Because liquids cannot be practically compressed, they do not change density under high acceleration such as performed in aerial maneuvers or space...

I ever read that there is no meaning for quantizing fluid mechanics. While left hand side of Einstein field equation used fluid-like approximation for matter (momentum-energy tensor). Therefore, if the first statement is correct then there is no meaning for quantizing gravity, right?

I saw the DAPL news story about the oil pipeline and I realized I have no idea how to analyze the problem of a fluid flowing from a boundary into granular material (or however you would classify soil). Does anyone know of any book or website that discuss the governing (or approximate) equations...

Hello all, I have browsed this forum occasionally when I had questions and threads showed up on a search. I have been stumped by a problem, so I decided to create an account and see if anyone could help me out! 1. Homework Statement A coal barge 1000 ft long and 100 ft wide is submerged in a...

Homework Statement A marine biology observation pod is being designed. It will be submerged, with vertical windows of various sizes and shapes. Calculate the total force being exerted on each of the windows described below. Density of water is 1000 kg/m^3...

1. The problem statement, all variables and given/known d At what speed, the velocity head of water is equal to pressure head of 40 cm of Hg? (1) 10.32 m/s (2) 2.8 m/s (3) 5.6 m/s Homework Equations v^2/2g = p/rho*g (velocity head= pressure head). The Attempt at a Solution since pressure head...

Why is there less pressure if the velocity of the fluid is increased?

Homework Statement What is the difference between these two formulas Homework Equations 1.Force=rho*g*h*area 2. Force=rho*g*volume 3. Force=rho*height*Area Where rho= specific weight of fluid The Attempt at a Solution I am guessing that 2 is for sphere or cylinders and for 3 i think it is...

Homework Statement The rectangular gate shown in section is 3 m long (perpendicular to the paper) and is hinged about its upper edge B. The gate divides a channel leading to a fresh-water lake on the left and a salt-water tidal basin on the right. Calculate the moment, M, on the shaft of the...

In fluid dynamics there is a duckbill check valve to prevent the reverse flow. In EM wave an antenna emmits/receive at the same efficiency. Is there anyway one can make a check valve for antenna so that it emmits more than received or vice versa...or perhaps emitts without even receive?

Homework Statement [/B] A rectangular object has a width of 40 meters, height of 15 meters, and length of 2 meters. It floats consistently when 3 meters of its height is below the surface of the water. 1. Find the volume of the displaced water. 2. How much is the buoyant force on the object...

Dear all, I have a question that has eluded explanation in fluid mechanics textbooks and even some of my colleagues. Suppose we have a general control volume. The application of linear momentum conservation will yield an equation of the form, $$\frac{\partial}{\partial t} \int_{V\llap{-}} \rho...

Hi folks, I have a pressure sensor working with arduino to measure depth. I want to calculate what I should see as a change in pressure if I move the tube horizontally under the surface of the water, keeping the tube opening parallel to the flow. I have calculated the dynamic pressure but...

Homework Statement A 1,500-kg car stands on a square platform, and a 25-kg boy stands on another square platform. These platforms are the two caps of a large oil-filled container. What must the ratio of the platform sides (large/small) for the boy to gently lift the car? -less than 1.5...

I'm curious if anyone knows of a good video of an extreme amount of pressure being applied to a sold amount of metal or other dense object. We're learning about fluids in my class, and naturally we discussed submarines, empty bottles, etc. but everything mentioned seemed to be hollow on the...

My son today asked me for an analysis of a situation, which was described to him as being purely anecdotal but apparently a fairly widespread belief among bartenders, so possibly correct. The description is that if you take the two metal halves of a cocktail shaker, with a normal compliment of...