2.5 Fluid Mechanics

0.0(0)

Studied by 0 people

Knowt Play

Learn

Practice Test

Spaced Repetition

Match

Flashcards

Card Sorting

1/24

There's no tags or description

Looks like no tags are added yet.

Study Analytics

Name	Mastery	Learn	Test	Matching	Spaced

No study sessions yet.

25 Terms

New cards

What is an" “incompressible” fluid ?

A liquid

In a liquid, molecules are weakly bonded, such that they can move around each other while staying close together. It has a surface when it is in a container.

New cards

What is a “compressible” fluid ?

A gas

No bonds link its molecules ; they move freely in space without natural interactions. So it gas occupies the entire volume of its container

New cards

What is the formula for the density ?

New cards

What is Pressure ?

Scalar quantity measuring the magnitude of the pushing force applied by this substance on a unit area of contact with a container

<p><strong>Scal</strong><span>ar </span><strong>quant</strong><span>ity </span><strong>measur</strong><span>ing </span><strong>t</strong><span>he </span><strong>magnit</strong><span>ude </span><strong>o</strong><span>f </span><strong>t</strong><span>he </span><strong>pushi</strong><span>ng </span><strong>for</strong><span>ce </span><strong>appli</strong><span>ed </span><strong>b</strong><span>y </span><strong>th</strong><span>is </span><strong>substa</strong><span>nce </span><strong>o</strong><span>n </span><strong>a</strong><span> </span><strong>un</strong><span>it </span><strong>ar</strong><span>ea </span><strong>o</strong><span>f </span><strong>conta</strong><span>ct </span><strong>wi</strong><span>th </span><strong>a</strong><span> </span><strong>contai</strong><span>ner</span></p>

New cards

How can Liquid develops pressure ?

Liquids develop pressure from “gravitational contribution” because the gravity field attracts the liquid downward, thus pushing on the bottom of the container. Being able to flow but blocked by the walls, the liquid pushes similarly on the walls.

So the pressure of a liquid increases with the depth of the liquid column. At a given depth level, the pressure of the fluid is identical at every point and in all directions.

New cards

What is the pressure of a column of liquid ?

New cards

Does Gravity impact gases ?

It’s negligible, but thermal contribution that develops pressure; increasing the temperature leads to an increase in molecular motion and, thus, more interactions with the walls of the container

New cards

What are the variations of the atmospheric pressure relative to the height ?

New cards

What is a barometer ? Describe the barometer experiment

device used to measure atmospheric pressure.

<p>device <strong>us</strong><span>ed </span><strong>t</strong><span>o </span><strong>measu</strong><span>re </span><strong>atmosph</strong><span>eric </span><strong>press</strong><span>ure.</span></p>

New cards

What is a Manometer ?

A manometer is a device consisting of an open U-shaped tube filled with a fluid and connected to a pressurized gas-filled tank.

It measures the gauge pressure of the gas.

<p><strong>A</strong><span> </span><strong>manome</strong><span>ter </span><strong>i</strong><span>s </span><strong>a</strong><span> </span><strong>devi</strong><span>ce </span><strong>consist</strong><span>ing </span><strong>o</strong><span>f </span><strong>a</strong><span>n </span><strong>op</strong><span>en </span><strong>U</strong><span>-</span><strong>shap</strong><span>ed </span><strong>tu</strong><span>be </span><strong>fill</strong><span>ed </span><strong>wi</strong><span>th </span><strong>a</strong><span> </span><strong>flu</strong><span>id </span><strong>a</strong><span>nd </span><strong>connec</strong><span>ted </span><strong>t</strong><span>o </span><strong>a</strong><span> </span><strong>pressur</strong><span>ized </span><strong>g</strong><span>as-</span><strong>fill</strong><span>ed </span><strong>ta</strong><span>nk.</span></p><p><span>It </span><strong>measu</strong><span>res </span><strong>t</strong><span>he </span><strong>gau</strong><span>ge </span><strong>press</strong><span>ure </span><strong>o</strong><span>f </span><strong>t</strong><span>he </span><strong>g</strong><span>as. </span></p>

New cards

What is gauge pressure ?

One defines the term “gauge pressure” Pg as the pressure measured relative to the atmospheric pressure

<p><span><strong>O</strong>ne <strong>defin</strong>es <strong>t</strong>he <strong>te</strong>rm “<strong>gau</strong>ge <strong>press</strong>ure” Pg <strong>a</strong>s <strong>t</strong>he <strong>press</strong>ure <strong>measu</strong>red <strong>relat</strong>ive <strong>t</strong>o <strong>t</strong>he <strong>atmosph</strong>eric <strong>press</strong>ure</span></p>

New cards

Is is the gauge pressure found with a manometer ? (“dormulas”

New cards

What does the Pascal’s Principles say about the forces on hydraulic lifters ?

New cards

About hydraulic lifters, what can you say about the liquid displacement ?

Since the liquid is incompressible, the downward displaced volume (input piston) is the same as the upward displaced volume (output piston)

resulting in a higher distance traveled by the input piston

<p>Since the liquid is incompressible, <strong>t</strong>he <strong>downw</strong>ard <strong>displa</strong>ced <strong>volu</strong>me <strong>(inp</strong>ut <strong>pist</strong>on) <strong>i</strong>s <strong>t</strong>he <strong>sa</strong>me <strong>a</strong>s <strong>t</strong>he <strong>upwa</strong>rd <strong>displa</strong>ced <strong>volu</strong>me (<strong>outp</strong>ut <strong>pist</strong>on)</p><p><strong>result</strong>ing <strong>i</strong>n <strong>a</strong> <strong>high</strong>er <strong>dista</strong>nce <strong>trave</strong>led <strong>b</strong>y <strong>t</strong>he <strong>inp</strong>ut <strong>pist</strong>on </p>

New cards

What is the work done at the input & output cylinders for hydraulic lifters ?

New cards

What is archimede’s principle ?

When a body is fully or partially submerged in a fluid, a buoyant force from the surrounding fluid acts on the body. The force is directed upward and has magnitude equal to the weight of the fluid that has been displaced by the body

<p><span><strong>Wh</strong>en <strong>a</strong> <strong>bo</strong>dy <strong>i</strong>s <strong>ful</strong>ly <strong>o</strong>r <strong>partia</strong>lly <strong>submer</strong>ged <strong>i</strong>n <strong>a</strong> <strong>flu</strong>id, <strong>a</strong> <strong>buoya</strong>nt <strong>for</strong>ce <strong>fr</strong>om <strong>t</strong>he <strong>surroun</strong>ding <strong>flu</strong>id <strong>ac</strong>ts <strong>o</strong>n <strong>t</strong>he <strong>bo</strong>dy. <strong>T</strong>he <strong>for</strong>ce <strong>i</strong>s <strong>direc</strong>ted <strong>upwa</strong>rd <strong>a</strong>nd <strong>h</strong>as <strong>magnit</strong>ude <strong>equ</strong>al <strong>t</strong>o <strong>t</strong>he <strong>weig</strong>ht <strong>o</strong>f <strong>t</strong>he <strong>flu</strong>id <strong>th</strong>at <strong>h</strong>as <strong>be</strong>en <strong>displa</strong>ced <strong>b</strong>y <strong>t</strong>he <strong>bo</strong>dy</span></p>

New cards

Give another formula for Fb :

New cards

What is the apparent weight of a body ?

When an object in a liquid needs to be lifted, the lifting force only needs to overcome the apparent weight instead of the entire real weight.

<p><strong>Wh</strong><span>en </span><strong>a</strong><span>n </span><strong>obje</strong><span>ct </span><strong>i</strong><span>n </span><strong>a</strong><span> </span><strong>liqu</strong><span>id </span><strong>nee</strong><span>ds </span><strong>t</strong><span>o </span><strong>b</strong><span>e </span><strong>lift</strong><span>ed, </span><strong>t</strong><span>he </span><strong>lifti</strong><span>ng </span><strong>for</strong><span>ce </span><strong>on</strong><span>ly </span><strong>nee</strong><span>ds </span><strong>t</strong><span>o </span><strong>overc</strong><span>ome </span><strong>t</strong><span>he </span><strong>appar</strong><span>ent </span><strong>weig</strong><span>ht </span><strong>inste</strong><span>ad </span><strong>o</strong><span>f </span><strong>t</strong><span>he </span><strong>enti</strong><span>re </span><strong>re</strong><span>al </span><strong>weig</strong><span>ht.</span></p>

New cards

WHat is viscosity ?

Viscosity is the resistance of a fluid against flow. It is analogous to friction for solids

New cards

What are the different types of “flow” ?

A flow is said to be “laminar” when the velocity at each point in the fluid is constant. The flow is smooth. It does not change or fluctuate.