Fluid Definition and 1000 Threads

I'm having fluid dynamics classes right now and I'm enjoying it very much (much more than my solid mechanics classes, by the way). Also, I do like programming and computer science, and CFD looks like a very interesting field. I'm developing a real interest for it. One question for those who are...

is there any way to derive p=rho/3 from 4 vector or stress-energy tensor?

1. A mass, M = 1.61 kg, is attached to a wall by a spring with k = 559 N/m. The mass slides on a frictionless floor. The spring and mass are immersed in a fluid with a damping constant of 6.33 kg/s. A horizontal force, F(t) = Fd cos (ωdt), where Fd = 52.5 N, is applied to the mass through a...

Homework Statement Using the matricial form of TFD (discret Fourier Transform) calculated : X=Fd(x) for x=(1,0,2j,1-j)^T from K^4 Homework Equations X=wx The Attempt at a Solution I know the "x" matrix and the "w" matrix but i don't know how to find the "ω" variable from the "w" matrix...

If we have a bottle with a fluid A of X density, and in the bottom of this bottle it magically spawns the same amount of fluid B with X/2 density, fluid B should rise in fluid A until they both change positions and fluid B floats in A. Wich property of the fluids are the ones that determinates...

Suppose we have a fan/blower that is working at sea level. It has a certain RPM against a specific voltage and current. We all know that. Now, that fan/blower has been brought to the top of a mountain where air is sufficiently less dense and the same voltage and current has been applied to the...

Homework Statement I need to find the amount of H2 being lost to water by being stored underneath a column of water. About 16 mL of H2 is made and it displaces the column by 16 cm. However the total amount of water is 30 ml/30 cm. I'm not sure which relationship to use to find the pressure of...

Hey All, I have a plastic vessel fully filled filled with an incompressible fluid (Water), at some time this vessel is impacted and crushed on one side (say 5% of the initial volume is lost). Only, I know the volume isn't lost, the fluid (being incompressible) will exert pressure on all...

Homework Statement I have problem of obtaining the cross sectional area . Homework EquationsThe Attempt at a Solution Taking section 2-3 as an example , my working is [ (3.3 +4.8) / 2 ]* 5 = 20.25 , but the ans provided is 29.28 , how to get the 29.28 ?

Hi, I was wondering if anybody has some experience with the mentioned book? I am to take a course in viscous flow and turbulence, and we are supposed to use White's "viscous fluid flow". I always like having a 2nd book, and I am considering Wilcox.

In the derivation of Navier Stokes equation there is a term for normal stress acting on the fluid element. While the cause of normal stress is the static pressure which is already present in the equation doesn't this mean that the same force on the fluid element is repeated twice with different...

I am stuck on the questions, 5.3.10 and 5.3.11 which are part of a chapter on dimensional analysis in fluid mechanics by Streeter. Question 5.3.10 (see also the attachment): It asks me for the given fluid dynamic problems, where is the inertial force not important. It lists several fluid...

1. Homework Statement A fresh water storage tank in a factory is shown in the figure above. Its top side is denoted as C, the narrow side as B and the long side as A. In order to allow regular maintenance and cleaning side A is hinged at its bottom edge and secured using a heavy-duty clasp at...

Hey guys. I could use some explanation since I am new to FM: So my problem is the following one: Fluid flows with an average velocity 8 m/s in a pipe with diameter 3m. What is the volume flow rate? Now, I think the formula I got to use is Q= v.A Yet, I found my solution from a formula I found on...

In Hawking-Ellis Book(1973) "The large scale structure of space-time" p69-p70, they derive the energy-momentum tensor for perfect fluid by lagrangian formulation. They imply if ##D## is a sufficiently small compact region, one can represent a congruence by a diffeomorphism ##\gamma: [a,b]\times...

Hi All, Looking for some help (any is greatly appreciated). I've been tasked with the below, and am unable to find a worked example to cross check my work against. If anyone with a greater knowledge than me could have a look at the below and advise if I'm right the right track. Thanks 1...

This is more of a concept question; if I choose different repeating parameters to someone else, say my lecturer, and got different pi groups to him/her, however my groups are still dimensionless (i.e. the units for each pi group cancel to 1), is my answer still correct?

Homework Statement More a report question but unsure where to put it. Take a 5mL syringe and a 10mL syringe (both filled to 5mL) with the plungers removed. Time how long it take to full drain each syringe Make a statement regarding your results. Homework Equations Fluid flow rate = volume /...

So I've noticed my little sister's helium balloons floating at the ceiling. Made me wonder if someone could create a device that could harvest energy from this buoyancy. What if I tied a very long rope to a huge balloon filled with helium, and rolled the other end of the rope to a gear attached...

I am looking at evaporating droplets and I am interested in looking at when there is azimuthal symmetry, and I need to write the Navier-Stokes equations for this. I just set all \varphi terms in the spherical case equal to zero right?

Homework Statement When a part of the channel is constricted , why will the Emin = Eo ? Homework EquationsThe Attempt at a Solution I just have the figure showing in case 1 and case 2, Emin = Eo without any explanation ... Can someone explain about it ? I tried to search many online resource ...

Hello, New to the forum, so apologies if this is not the correct sub-category. I am testing compliances of materials by filling balloons with different fluids. I do this by filling up a 30 mL syringe with fluid and placing it into an infusion pump set to infuse at a rate of 0.1 mL/min. The...

Homework Statement ρ= density, vi = i-th velocity component, gi=i-th component of gravity vector, p=pressure, μ= viscosity, D/Dt = material derivative Homework Equations Continuity equation: div v = 0 The Attempt at a Solution

My native language is not English. I follow a series of vids about Ansys Fluent. I am not stuck in 2.59 about the part "so VR" and "so we are in a velvet in laminar regime." Would you please explain those parts. This is about my project and it is about calculation of pressure losses in pipes in...

Hi, so someone probably has already asked this, but does temperature increase or decrease with depth in a fluid? I thought it would decrease since it has more pressure but it is probably wrong, or doesn't make sense. I was confused because the ocean gets colder the deeper you go, but then does...

Homework Statement The velocity of efflux of a liquid through an orifice in the bottom of the tank does not depend upon: A. Size of orifice B. Height of the liquid C. Acceleration due to gravity D. Density of the liquid Homework EquationsThe Attempt at a Solution My textbook says that...

Hi I'm trying to understand a paper that approximates the solution to Burger's equation (1D Navier Stokes) by a doing a one-dimensional cellular automaton simulation. I'm having a hard time understanding how all these topics connect. I have seen and walked through various demonstrations that...

Moving fluids are generally in a state of non-equilibrium. However, in fluid dynamics, people generally assume a state of local thermodynamic equilibrium and argue that in such a condition, equilibrium thermodynamic concepts such as pressure, temperature, entropy, internal energy etc. can be...

Hello, I am reading a book about simulation, modeling and automatic control. In a chapter about hydraulic transmission line, a pipe's "bandwidth" is mentioned. Contex: "Long pipes are used in large hydraulic installations where pipes of length up to 10 m are not uncommon. Moreover, in offshore...

If you have an non-viscous incompressible fluid flowing in a pipe whose static pressure is higher than atmospheric pressure, then after exits the pipe will the dynamic pressure increase? The static pressure of the fluid right after exiting should decrease because it should be equal to the...

Hi, Does anyone know of any fluid that emits light when current is running through it? Why? To feed to a flower, apply low voltage and make it glow. Florescent light isn't enough and bioluminescence isn't my area of expertise so turning a flower into a LED is going to be my approach. All tips...

Homework Statement Mercury is added to a cylindrical container to a depth d and then the rest of the cylinder is filled with water. If the cylinder is 0.8 m tall and the pressure at the bottom is 1.3 atmospheres, determine the depth of the mercury. (Assume the density of mercury to be 1.36 104...

Homework Statement A pump with inlet of saturated liquid at 600kPa has an exit stream of 10MPa calculate work Homework Equations Energy balance equation Entropy balance equation Linear interpolation Steam table The Attempt at a Solution My attempt at the solution was to calculate the entropy...

Hi all, I encountered a fairly straightforward problem involving fluid dynamics, but the result I got is very confusing and I seem not to understand where I got wrong. This is the question: A rectangular flat-bottom barge with a bottom area A=50 m2A=50~\text{m}^2A=50 m2 is loaded so that the...

So I was playing around with Fluid Pressure and Flow over on PHET animations and noticed something odd. When a fluid with high flow rate is going from a large pipe to a small pipe a lower density increases the pressure. And a higher density lowers the pressure in the narrow part of the pipe. My...

I am looking at a proof from a book in fluid dynamics on time differentiation of fluid line integrals - Basically I am looking at the second term on the RHS in this equation $$ d/dt \int_L dr.A = \int_L dr. \partial A / \partial t + d/dt \int_L dr.A$$ The author has a field vector A for a...

Homework Statement A water jet hits a wall and splits into two streams (see attachment). The jet carries 3kg of water per second. The cross-sectional area of the flow at (2) is A = 2*10^-3 m^2. The average velocities at the outlets are V2 = V3 = 1m/s What is the net vertical force exerted by...

1. Homework Statement I did an experiment to separate different sizes of starch particles (range of size 1 µm to 10 µm). I mixed the starch powder with water in a long cylinder. I have to create model by using long cylinder to separate those starch particles according to their size (<1µm...

Hi all, I study Mathematics and Theoretical Physics at university. Next year, I'll have a choice between three modules; Thermodynamics and Statistical Physics Cosmology Fluid Mechanics My main interest is Condensed Matter Physics; therefore, thermodynamics and statistical physics is a given...

Hello all, I am posting this question here in this thread and not the homework thread since it is not a homework problem but something I have been working on myself. Let us imagine a fluid flowing through a pipe, we can measure pipe diameter and fluid velocity. The density of the fluid is also...

The stress-energy tensor of a perfect fluid in its rest frame is: (1) Tij= diag [ρc2, P, P, P] where ρc2 is the energy density and P the pressure of the fluid. If Tij is as stated in eq.(1), the metric tensor gij of the system composed by an indefinitely extended perfect fluid in...

Hey guys, I am trying out an idea. I want to see if I can make an electrostatic fluid accelerator inflate a balloon. Attached is an image of a concept I came up with that works a little differently. Before I dive in, I was wondering if anyone on the forum could tell me if my concept might or...

Hello everyone! I am new to these forums and glad to see a great community helping out each other. I have a question regarding a solenoid valve design. What should be the design ethics and safety considerations for a 240 volts AC connected solenoid valve that is used for a cryogenic vessel...

Hello there. I took a test yesterday in my thermal fluids 1 class and I was hoping somebody could confirm or critique my answer. (Don't worry, I asked the professor first if I could take the picture) The problem is: Water is pumped from a lake to a pool through a 0.05 m diameter pipe. System...

Hello, How do you calculate the terminal velocity of a fluid through a pipe. My problem includes turbulent flow, very high reynold number, and water (incompresible).

Hello, I have a general question regarding energy coupling in multi phase flow. My question comes is based on the text from this book...

Hi all! I'm currently working with epoxies and very viscous silicone oils. The problem is when I mixing the two part epoxy, there will be a lot of bubbles in the resin. I managed using heat gun to break air bubbles near the surface, but the bubble at bottom of the mold cannot flow up. I know...

Hello, I'm a physician with special interest in cardiovascular physiology. I'm trying to comprehend the basic physics of the cardiovascular system. Here's my thought process - Simply stated - the heart muscle contracts, thereby causing a reduction in the cardiac chamber volume and release of...

Homework Statement Homework Equations The Attempt at a Solution I tried a few different things, they all involve finding u and v components of velocity. I know the stagnation point is at y = 0. I also know that at stagnation u = v = 0. If I get the velocity magnitude and set it equal...

Hi all, I have a little problem while reading Feynman lecture note volume 2, chapter 40, section 40-3. In that section Mr Feynman talked about Bernoulli equation and a example of a filled water container. In high school we learned that if we drill a hole near bottom of container, we can get...