# What is Fluid mechanics problem: Definition and 34 Discussions

Fluid mechanics is the branch of physics concerned with the mechanics of fluids (liquids, gases, and plasmas) and the forces on them.:3
It has applications in a wide range of disciplines, including mechanical, civil, chemical and biomedical engineering, geophysics, oceanography, meteorology, astrophysics, and biology.
It can be divided into fluid statics, the study of fluids at rest; and fluid dynamics, the study of the effect of forces on fluid motion.:3
It is a branch of continuum mechanics, a subject which models matter without using the information that it is made out of atoms; that is, it models matter from a macroscopic viewpoint rather than from microscopic. Fluid mechanics, especially fluid dynamics, is an active field of research, typically mathematically complex. Many problems are partly or wholly unsolved and are best addressed by numerical methods, typically using computers. A modern discipline, called computational fluid dynamics (CFD), is devoted to this approach. Particle image velocimetry, an experimental method for visualizing and analyzing fluid flow, also takes advantage of the highly visual nature of fluid flow.

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1. ### Fluid mechanics problem: The extent to which an iron deposit can influence water level

what i understand i have to do is find the formula for the potential energy with this iron deposit and substract it from the potential energy before this iron deposit was placed there. I found the solution but i do not undsrstand why the formula for potential gravitation energy was used. what i...
2. ### Bernoulli vs. Reynold Transport Theorem Problem for Raincap

Hi, I am trying to map out the forces that act on a raincap installed at the end of a pipe, but I have ran into a problem where I am getting 2 different equations depending on the method that I use. I'm definitely missing something here and I was hoping someone is about to point it out to me...

5. ### Fluid Mechanics problem: Oil pressure calculations in pipe flow

Problem Statement: An oil with density 900 kg/m3 and viscosity 0.18 Ns/m2 flows through a circular pipe which inclines upwards at 40° to the horizontal. The length of the pipe is 10 m and the diameter is 6 cm. The fluid pressure at the lower end of the pipe is 350 kPa and the pressure at the...
6. ### A fluid mechanics problem -- Shape of a falling water drop

Homework Statement A drop of water fall towards the ground with initial mass [m][/0] and radius [r][/0] (assume the initial shape of that water drop is sphere). the air resistance is F=½.ρ.A.[v][/2].C (C is the drag coefficent, A is the area that the air contact with the water drop and ρ is the...
7. ### Determine Force on 6ft Door Due to Water & Air Pressure

Homework Statement Determine the total force and its direction (left or right) due to water and air pressure in the surface shown in Fig. P3.62 (lb f). The door is hinged at the top and is 6 feet wide. See attached image.Homework Equations Fp (force of pressure) = specific weight of fluid *...
8. ### Question about pressure drops due to friction and valves

If I'm designing an injector for a rocket engine, I have a specific mean flow rate (m/s) that must be met due to the pipe diameter and the required mass flow rate. I've calculated all the pressure drops due to lost work from friction, valves, and orifice geometries (not from change in area, but...
9. ### Calculating Gauge Pressure on a Sphere

Homework Statement Homework Equations What is gauge pressure ? The Attempt at a Solution How to find gauge pressure ?
10. ### At what distance does a seaplane's boundary layer transition to turbulence?

Homework Statement A seaplane flies at 100 mph through air at 45 *F. At what distance from the leading edge of the underside of the fuselage does the boundary layer transition to turbulence? Homework Equations Re = pvL/u Re is Reynolds number p (rho) is the density V is the characteristic...
11. ### Law of continuity problem in fluids

When a hose with running water is partially blocked with our finger ,the water comes out with a greater velocity. This is in agreement with the law of continuity in fluids which states that velocity of fluid is inversely proportional to the area of cross section. But when a running tap is...
12. ### Air Flow through cooling tower- fluid mechanics problem

Hey everyone! I am working on improving natural draft counter flow cooling tower efficiency as my final year B.E. project. I came across a research paper that said that at transverse cross section of the tower, above drift eliminators, the air velocity decreases from the periphery to the...
13. ### What is the Relationship Between Pressure and Height in Fluid Mechanics?

The correct answer to this problem is h2 = h1 but I don't get it. According to what I understand, F=p/A So for the Tube on the left: F1 = P/A = (\rho*g*h1)/A1 For tube on the right: F1 = P/A = (\rho*g*h1)/3*A1 I get h2=3h1 (i know if you think about it this does not make sense...
14. ### Fluid Mechanics problem - cylinder over a orifice

Homework Statement The horizontal bottom of a wide vessel with an ideal fluid has a round orifice of radius ##R_1## over which a round closed cylinder is mounted, whose radius ##R_2>R_1##. The clearance between the cylinder and the bottom of vessel is very small, the fluid density is ##\rho##...
15. ### Simple Fluid mechanics problem

Homework Statement A uniform wooden stick of density d is completely immersed in water of density D (D>d). One end of the stick is free to rotate about a hinge which is attached to the wall of the container. In equilibrium the stick the stick makes an angle θ then tanθ is- (a)0 (b)d/D...
16. ### Fluid mechanics problem, need explanation please

Hi please check the highlighted question in the attachment and the solution and see the problem, i need help please. I have two questions about it: 1- why didn't we take the plug as a vertical wall and thus the force would be integral of pressure x area? 2-WHERE DID THE FORCE DUE TO...
17. ### Fluid Mechanics Problem Creating a Mesh

We are beginning a project in my Intermediate Fluids class to make a program that can do aerodynamic analysis on an air foil. First, given any three nodal coordinates (x,y) of a triangle, we must write a program to compute its surface vectors and area of the triangle. The nodes will be in...
18. ### I need help with a Fluid Mechanics problem

the probem is from the book: Fundamental mechanics of fluids by I.G. Currie is from the chapter 4 ( 2 dimentianal potential flows ) is the problem 4.4: . Consider a source of strength m located at z = −b , a source of strength m located at z=- a^2 / b , a sink of...
19. ### Fluid mechanics problem involving a hose and water coming out.

Homework Statement Homework Equations I am having some trouble starting this problem. At first look I would say that a conservation of mass will give V1*A1=V2*A2 for steady state incompressible fluid. Then I would solve for A2 and relate the two diameters but I don't have the velocity...
20. ### Calculating Resultant Force on a Moving Blade Impinged by a Jet of Water

A jet of water 70mm in diameter moving with a velocity of 25m/s impinges tangentially on a stationary blade which deflects the jet through 130o. (a) Find the resultant force on the blade, in magnitude and direction. (b) If the blade has a velocity of 5m/s in the same direction as the jet and...
21. ### Fluid Mechanics: Pressure Calculation for a Horizontal Bend in a Pipeline

Homework Statement A horizontal bend in a pipeline conveys water at a discharge at 1000l/s gradually reduces from 600mm to 300mm and deflects the flow through an angle of 60 degrees. At the larger end the pressure is 170000N/m^2. Determine the magnitude and direction of the force exerted on...
22. ### Pipe bend fluid mechanics problem

Homework Statement The pipe shown has a 180° horizontal bend in it as shown, and D is 20 cm. The discharge of water (ρ = 1000 kg/m3)in the pipe and bend is 0.30 m3/s, and the pressure in the pipe and bend is 100 kPa gage. If the bend volume is 0.10 m3 and the bend itself weighs 500 N...
23. ### Can Suction Lift a 20 Meter Water Column Without Exceeding Its Tensile Strength?

Homework Statement What suction (or negative pressure) is required to support a column of liquid 20 m high? Does this exceed the tensile strength of water? Homework Equations Bulk Modulus = (Change in Pressure/ (Change in Volume/Volume)) Pressure = Force / Area The Attempt at a...
24. ### Pressure Variation in a Tilted Fluid Column

Homework Statement A 0.3 m long tube is filled with sterile solution of density 1037 kg m-3 and closed at the top. The tube is tilted at 40°. to the horizontal. The gauge pressure at the base of the tube is 3000 Pa. What is the gauge pressure at the top of the tube (in Pa)? Homework...
25. ### Fluid Mechanics Problem: Evacuating a Tank with Vacuum Pump for Ideal Gas Air

Homework Statement 6. A tank filled with air of initial density ρo=1.2 kg/m3 and initial pressure Po=100 kPa is to be evacuated by a vacuum pump. The tank volume is 1 m3 and the pump evacuates 0.0013 m3 of air per second regardless of the pressure. The process is isothermal and for an...
26. ### Need help with fluid mechanics problem set by lecturer :[

Note: Have been taught nothing about fluid mechanics yet, this task was set to help develop self learning skills, yet with some research I've carried out I'm still at a brick wall so i hope you don't mind helping me! Homework Statement Explain the phenomenon that causes a noticeable...
27. ### How to Calculate Foam Volume for Buoyancy Support of Cargo Block

Homework Statement Determine the volume of foam needed to support one cargo block with the following conditions. The bottom of the block is 2 cm above the water line and when viewed from the top there is 1 cm of foam around all edges of the cargo block. The dimension of the block are 3.5...
28. ### Mechanical Engineering Student with Fluid Mechanics Problem

Hey everyone! I'm having difficulty and wondering if someone would be kind enough to help me figure out how to approach this problem. I'm a mechanical engineering student and reasonably new to fluid mechanics, and quite confused. :blushing: Thanks for any help anyone can give me :smile...
29. ### Engineering fluid mechanics problem

PLEASE, I NEED TO KNOW HOW START THIS PROBLEM. CAN I USE BERNOULLI'S EQUATIONS?. HOW? A hydroponic garden uses the 10 m long perforated pipe system to deliver water at 20ºC. The pipe is 5cm in diameter and contains a circular hole every 20 cm. A pump delivers water at 75 kPa (gage) at the...
30. ### What is the pressure on Pike's Peak above Denver, CO?

At ground level in Denver, Colorado, the atmospheric pressure and temperature are 83.2 kPa and 25 degrees Celsisus. Calculate the pressure on Pike's Peak at an elevation of 2690 m above the city assuming an incompressible atmosphere.
31. ### What is the force exerted by the water on the bottom of the tank?

I am having great trouble understanding this problem and the way to solve it, could anyone explain in detail? Any help is appreciated!:smile: 1) An aquarium tank is 80cm long, 30cm wide, and 35cm deep and is filled to the top. What is the force of the water on the bottom of the tank, with...
32. ### Another Fluid Mechanics problem

I'm having problem understanding this one, can clarify and help answer? A material region is defined as one where the surface velocity W is everywhere equal to the fluid velocity V. Such a region always contains the same fluid. Is it possible to define W in a less restrictive way and still...
33. ### Solving a Tricky Fluid Mechanics Problem

Hi. i am trying to brush up on my fluid mechanics for when i do it next year at uni. do any of you guys have any idea how to solve the follow question? 'A suction pump moves water from a reservoir to a holding tank. The system is designed in such a way that the suction pump is inclined...
34. ### What is the shape of a rotating mercury surface in an astronomical telescope?

Been looking through my notes for a basis to start this question but can't seem to find a starting basis due to poor handouts (or more likely bad note taking by me) Heres the question A cocnave astronomical telescop mirror may be made by rotating a circular tank of mercury. Find an...