Fluid Definition and 1000 Threads

  1. S

    Fluid Hydrostatics: Homework Solutions & Explanations

    Homework Statement Attached below Homework EquationsThe Attempt at a Solution My first confusion is with the pressure measuring device, i just converted the units into Pa by dividing by 1.02x10-5 such that: Pressure at the top of the tank = (0.07/1.02e-5) - (9800*0.3) = 3922.75Pa So on the...
  2. Y

    Faster, narrower fluid same pressure as slower, wider fluid?

    Say, I have a garden hose. You know the thing when you cover a part of the hole to make the fluid reach farther because it's faster, right? Say you're pointing it down and there's no air resistance or gravity. You're hitting a surface with the hose and there's a device that measures how much...
  3. U

    Energy-Momentum Tensor of Perfect Fluid

    Homework Statement I am given this metric: ##ds^2 = - c^2dt^2 + a(t)^2 \left( dx^2 + dy^2 + dz^2 \right)##. The non-vanishing christoffel symbols are ##\Gamma^t_{xx} = \Gamma^t_{yy} = \Gamma^t_{zz} = \frac{a a'}{c^2}## and ##\Gamma^x_{xt} = \Gamma^x_{tx} = \Gamma^y_{yt} = \Gamma^y_{ty} =...
  4. SurajBahuguna

    How to determine shape of surface of a fluid?

    I have been told by my teacher that the surface of a fluid is always perpendicular to the net force acting on it. The reason being a fluid can not withstand tangential stress and if a shear stress is applied to it, it will slip until the surface becomes perendicular to the net force. So my...
  5. ManicPIxie

    Bernoulli, Fluid Dynamics, and ships

    Homework Statement The Plimsoll line is a line marked on the side all ships that effectively indicates the safe maximum load the ship can carry in that type of water at that temperature.You have been asked to stand on the dock and collect the tickets of the passengers boarding a cruise ship...
  6. J

    What Are the Best Fluid Mechanics Textbooks for Self-Study?

    Hello! My name is Josh Currently going into third year physics. My university does not offer a single course involving fluids except the most basic intro to bernoulli's equation. So, I thought I would make it my own project for the summer to learn some fundamentals. I was wondering if anyone...
  7. Nicky_Boy02

    Pressure, Temperature and Fluid phase change

    Some please clear my confusion here, when you compress a fluid the temperature increases. Since the temperature increases (fluid gets warmer), why is the fluid condensing from gas to fluid? when temperature increases, isn't that the fluid will evaporate? This has been bugging for awhile...
  8. C

    Have You Calculated Mass Flow Rate Correctly in Fluid Dynamics?

    I've Attached the question and my answer to question 1 to task 3 and guidance if I've done it right? Or any guidance?
  9. J

    Question about Fluid Mechanics, pumping

    Homework Statement The water in the bottom tank (position 1) is pumped into!the!roof tank (position 2) through a long pipe (containing two elbows a and b separated by 1 meter) which discharges freely at a height 50 cm above the liquid surface in the upper tank. To fill up the upper water tank...
  10. S

    Velocity of Fluid flow due to gravity

    I am designing a system for an engineering project at school. It's essentially a clock to be powered by water turning a mechanical system of gears (not generating electricity). Imagine a rectangular basin full of water placed at some height above the ground. There is a hole in the bottom...
  11. squelch

    Pressure of a fluid contained in a steel container

    Homework Statement A steel container is completely filled with gasoline, and then sealed. The temperature is then increased 11 degrees C. If the bulk modulus of gasoline is 1.90 \times {10^9}Pa, find the increase in pressure of the gasoline if: (a) The expansion of the container is considered...
  12. SnakeDoc

    A simple Fluid Dynamics/Pressure HW question

    Homework Statement A piston of cross-sectional area a is used in a hydraulic press to exert a small force of magnitude f on the enclosed liquid. A connecting pipe leads to a larger piston of cross-sectional area A (the figure). If the piston diameters are 3.63 cm and 50.7 cm, what force...
  13. M

    Verifying Stokes' Flow for Fluid Motion Around a Sphere

    Homework Statement Let a spherical object move through a fluid in R3. For slow velocities, assume Stokes’ equations apply. Take the point of view that the object is stationary and the fluid streams by. The setup for the boundary value problem is as follows: given U = (U, 0, 0), U constant, find...
  14. S

    Bernoulli's equation and fluid movement

    hello! I think Bernoulli's equation it's just an equation of conservation of energy. Am I right? but I don't understand how to apply the conservation of energy principle exactly. can you help me please? I get it that if the fluid moves, it has kinetic energy which is 1/2mV^2. I also get...
  15. T

    Magnetic field due to flowing charged fluid

    Hey, I've been wondering about the behavior of flowing charged particles lately. In particular, imagine that I have a tank of charged fluid. Lets assume this charge density is 1 C/cm^3. I then allow the fluid to flow through a pipe of 1 cm^2 cross-sectional area at a rate of 1 m/s. Thus there...
  16. Feodalherren

    Fluid Mechanics: viscous flow in pipes

    Homework Statement Homework Equations ρ=789, μ=.0012 The Attempt at a Solution From the energy equation we get hf=0.9 We know that hf=f(L/D)(V^2)/(2g) [sorry don't know how to use latex after they removed the bar on the right] Now I can substitute V for Q, but I'm stuck with f and Q as...
  17. M

    Modeling Deceleration of Object Towed in Water

    So this is about a modelling project I'm doing. If you have an object that was being towed in water and the towing force is suddenly removed. There is a force F=1/2(density of fluid)(C constant)(A)V^2 that acts on the object. I am trying to find the distance X it will take for the object to...
  18. ryanuser

    Fluid that is a permanent magnet at room temperature?

    Hi Is there any fluid that is a permanent magnet at room temperature? (Ferrofluids do not retain their magnetic effect hence temporary). Thanks
  19. U

    Hydrostatics on plane surface (basic fluid mechanic Q)

    I don't understand how they got the "position of individual forces". For F1, I'm guessing they used a pressure diagram and that's why it's 2/3 from the tip of the triangle. But why wouldn't the force act on the centroid for this square section (thus its 3.5/2)? But for position of F2 (y2)...
  20. A

    Exploring Advective Acceleration in Fluid Mechanics

    I am just starting on this subject and I am trying to get a feeling for the concepts. One thing that confuses me a lot is the idea of an advective acceleration. We have that the rate of change of the velocity in a fluid is given by the material time derivative: Dv/Dt = ∂v/∂t + (v⋅∇)v Now in...
  21. M

    Simulation error messages solidworks - invalid goals

    I am running a simulation on a flat plate heat exchanger and the solver is coming up with some error messages. The first says that a vortex crosses the pressure opening and the second says that my heat transfer rate goals are invalid. How can I get the heat transfer goals to be valid as I need...
  22. andyrk

    Direction of pressure in a Fluid

    Have a look at this link guys: http://ocw.mit.edu/courses/mechanical-engineering/2-016-hydrodynamics-13-012-fall-2005/readings/2005reading2.pdf. Could someone explain the term − 1/2 ρ(b∆x∆z) in equation 2.2? I don't understand how does that represent force on the plane along z-axis.
  23. S

    Nozzle problem between subsonic and supersonic speed & nozzle area

    Hi all, I have really a confusion between subsonic and supersonic speed evolution when the area decrease or increase I have a problem to understand why in supersonic regime the velocity evolution in a nozzle is adverse of the subsonic regime? for example in subsonic regime, when the area...
  24. AdityaDev

    How does the melting of ice affect the oil-water interface in a fluid system?

    Homework Statement A cube of ice is floating in water such that some part of the ice is submerged. Oil is poured on the water.( so water on the bottom, oil on top and ice in between). When the ice melts completely, the level of oil-water interface ______(rises/falls) and the top level of oil...
  25. R

    Need help re: air pressure to fluid pressure

    Hi, I'm working on a project and need a bit of help, since I don't want to kill myself. My question is this: If I have a cylindrical tank (think a big scuba tank) half full of liquid, half full of gas (let's just say it's water/air) and start heating up the liquid, I know that pressure will go...
  26. L

    What is the resultant force exerted by the sides of the glass on the water?

    Homework Statement A glass full of water has a bottom of area 20 cm 2 , top of area 20 cm 2 , height 20 cm and volume half a litre. (a) Find the force exerted by the water on the bottom. (b) Considering the equilibrium of the water, find the resultant force exerted by the sides of the glass on...
  27. L

    Classical I need a fluid mechanics textbook

    Hello, everyone, please forgive me for my poor English. I'm a sophomore, major in Astronomy. I've finished Hassani's book(Mathematical Physics). And I've learned Real variable function and functional analysis (I do not know what exact name of this course) I'd like to buy a textbook with...
  28. M

    How Does Bulk Modulus Affect Water Compression in a Tank?

    Hey all, I am having trouble getting to the answer of the attached file below. It would be appreciated if anyone had some tips on getting to the answer.
  29. B

    Molecular Modeling of Fluid Mechanics

    As I've been reading up on fluid mechanics recently, I've discovered several different molecular models which attempt to explain heterogeneous fluid flow from a molecular level. Classical fluid mechanics assumes that hard body approximation- that atoms are hard spheres knocking into each other...
  30. A

    Drawing up a liquid by forward motion of a tanker

    Homework Statement We are in a planet where the gravitational acceleration is 1 ms-2. Tankers fly over the surface of a liquid ammonia lake (at 239K) at a height of 40m. A special, insulated, frictionless tube is lowered into the ammonia 1m below the surface. We want to draw up ammonia through...
  31. Feodalherren

    Computational fluid dynamics: steady 2D flow

    1. Homework Statement Homework Equations CFD The Attempt at a Solution I'm a bit confused by this question. So at first what I do for the problem on the left, I find the changes in the velocities in X and and Y on all four sides. I notice that the values on the diagram to the left are...
  32. Feodalherren

    Fluid Dynamics: Conservation of momentum equation

    Homework Statement Homework Equations Conservation of linear momentum for fluids The Attempt at a Solution This seemingly simple problem has me confused. First of all, I want to set up the sum of the foces as: -Min + Mout -Fx = 0 So first of all, not only does my Fx term have the wrong...
  33. Wyn

    Other Intr. Fluid Mech. for Physicists and Mathematicians by Pert

    Any thoughts on this book? I'm interested in a fluid mech book for physicists, this one looks good but I can't find any reviews on it. You can suggest other books as well, as long as they have available new editions.
  34. Saumya Kar

    Difference between acoustic pressure and fluid pressure

    While the sound waves travel in a medium, let's say a fluid, what is the difference between fluid pressure and acoustic pressure ? Are these entities same?
  35. Q

    Problem of fluid -- Blocks, pulley, two fluids

    Homework Statement dynamic viscosity 1 = 1125 2 kgf-s / m2 , dynamic viscosity 2 = 62.5 2 kgf-s / m2 , Areas: A1 = 20 cm2 , A2 = 50 cm2 W1 = 15 Kgf, W2 = 40 Kgf. The block (2) is displaced downwards with a constant speed of 80 mm / sec, whereas linear velocity distribution determined: 1) The...
  36. Z

    Finding density of fluid from a mass on a spring in fluid

    http://imgur.com/rE7jLlC When setting up the sum of forces I had an unknown value for the spring, buoyancy, and normal force. What I tried was setting up a triangle to find the length of the spring, which was 1.039m with that I could find the force acting on the spring, 4.3N, which would be the...
  37. A

    Fluid dynamics question (Poiseuille)

    Hi, I'm attempting to do a question involving blood flowing through a blood vessel and I'm incredibly stuck and would appreciate some help. The question is as follows: 'A simplified model of blood flow through the human body makes the approximation that the flow I is proportional to the pressure...
  38. A

    Calculation of the force exerted by a liquid

    Question: The height of the given vessel is h,and the width of the given vessel is b (as given in the diagram). The density of the liquid is r.Find the force exerted by the liquid on the slant wall. Relevant formulae : P = F/A F = Vdg An attempt at the solution...
  39. Q

    Fluid problem -- Piston moving in an oil-filled cylinder

    Homework Statement A piston 10 is coaxially in diameter moves within a cylinder whose inner diameter is 10.006 in; The annular space between piston and cylinder is filled with oil having a kinematic viscosity is 0.004 feet ^ 2 / s and specific gravity of 0.85 If the piston makes its way with a...
  40. A

    Pressure and normal stress in fluid mechanics

    Hi, everyone. I am learning fluid mechanics. One book says that for a infinitesimal fluid cell, surface force includes 1) the pressure, which is imposed by the outside fluids surrounding the concerned fluid cell 2) the shear and normal stress, which result in shear deformation and volume...
  41. Feodalherren

    Newtonian fluid mechanics: Navier-Stokes equation

    Homework Statement Homework Equations Navier-Stokes The Attempt at a Solution Not really trying to solve a problem, trying to understand what is going on in my textbook. So look at the stuff in red first. I see where all that is coming from, it's clear to me. However, the stuff in green...
  42. L

    Do diabetics have sugary interstitial fluid?

    So my understanding is that capillaries leak out their blood plasma containing sugar and other nutrients insulin (when sugar present)near body cells, and this is what comprises interstitial fluid. But what if no insulin is present (Type 1 diabetes) or insulin creates no response (Type 2...
  43. Dennydont

    Velocity of fluid in venturi tube

    Homework Statement A venturi tube is a means of measuring fluid velocity. One particular device consists of a level, circular pipe of radius 5.7 cm which at one point narrows to a radius of 3.7 cm. An ideal, incompressible liquid flows through the tube and the pressure difference between the...
  44. L

    Fluid statics- pressure intensity and hydrostatic force

    Homework Statement a concrete dam, 20m in height, has a vertical upstream face. if the water level is coincident with the top of the dame, calculate and plot the pressure intensity at 4m intervals over a vertical and thus determine the total hydrostatic force acting per unit width. Show that...
  45. D

    Fluid mechanics: intuition about the 'convective' term

    Hi, I am doing an introductory course on fluid mechanics, and I'd like some intuition (that's why I'm posting on the engineering forums and not on the math forums, even if I'm studying for a degree in math) about the concept of the total derivative and, particularly, its convective component...
  46. T

    Fluid dynamics - find velocity of a particle in a vector fie

    Homework Statement Determine the speed of a fluid particle at the origin and at a point (1,-2,0) for each of the following velocity fields when t = 2s. All distances are in meters and t is in seconds. V = (x+2)i + xtj - zk m/s Homework Equations V x dr = 0 dV/dt = u(dV/dx) + v(dV/dy) +...
  47. T

    Pressure and velocity calculation for microchannel. pls help

    Me and my friends have been trying (b) for soooo long! we have gone to PhD students and some fluid dynamic doctors for held and they cannot figure this out. 1. Homework Statement 2) This question concerns the design of a ‘micro-chemostat’ device. E. coli exhibiting chemotaxis can swim up to...
  48. Feodalherren

    Fluid Mechanics: Hydrostatic Pressure on a gate with hinges

    Homework Statement Homework Equations Fluid Mechanics The Attempt at a Solution Lets start with the easy part: The pressure of the air is constant so the pressure will act as if it's a concentrated force on the center of gravity of the gate. F = PA = (10,000Pa)(.3)(.6)=1800N The moment...
  49. M

    Venturi, how does fluid go from low P tube to high P tube

    Homework Statement How does fluid move from low pressure area in a Venturi to a high pressure area, which is downstream from the Venturi. Homework EquationsThe Attempt at a Solution Not understanding the mechanism here, as I thought fluids only go from high pressure to low presure. Since the...
  50. Feodalherren

    Fluid Mechanics: Manometry - Fluid through a pipe

    Homework Statement Homework Equations Hydrostatic equation The Attempt at a Solution Call length from 2 to the Hg "h". Yhg = specific weight of Hg, from book = 846lbf/ft^3 Yw= water = 62.4 lbf / ft^3 Then P2 = P1 + Yw(5sin45 + h + .5) - Yhg(.5) - Yw(h) Then P2 - P1 = simplify and plug in...
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