# Pressure

Better Essays
Topics: Pressure
Module EG1083 Fluid Mechanics

PRESSURE , FLUID SYSTEMS and FLUID PRESSURES

SM(1)

Pressure
Definition of Pressure

Fluid pressure: Force per unit area exerted by a fluid in a solid wall. Force acts perpendicularly to the surface in contacts. Fluid is a co u d s common word for gas a d/o liquid. o od o and/or qu d Pressure is a scalar quantity. It has the units of: N/m2 or Pa (or kPa) in SI system of units psi in Imperial system of units Pressure can also be expressed in terms of height of a column of liquid List of units of pressure measurements & conversion of units Pascal s Pascal’s law

Scalar quantity

Units of Pressure

SM(2)

Pressure
Pressure measurements Absolute pressure Gauge Pressure

...divided into three different categories: 1. Absolute pressure – which is defined as the absolute value o pressure (force-per-unit-area) ac g o of p essu e ( o ce pe u a ea) acting on a surface by a fluid. su ace ud Abs. pressure = pressure at a local point of the surface due to fluid – absolute zero of pressure (see page 63 of lecture notes) 2. Gauge pressure – difference between abs. pressure and atmospheric pressure – is always positive 101.325 kPa or 14.7 psi

Equations

Pressure term relationships

– a –ve gauge pressure is vacuum ve vacuum. Pressure term relationships • Abs pressure = gauge pressure + atm pressure Abs. • Abs. pressure = – gauge pressure + atm pressure (vacuum) > atm < atm
SM(3)

Pressure
Pressure measurements

Relation between abs., gauge and vacuum
Absolute pressure Gauge Pressure

gauge

Equations gauge) Pressure term relationships

SM(4)

Pressure
Pressure term relationships Hydrostatic pressure

3. Differential pressure – measurement of an unknown pressure minus the reference to a o e u e e e ce o another unknown p essu e o pressure. – it is used to measure differential pressure i.e. pressure drop (ΔP) in a fluid system

SM(5)

Fluid systems and Fluid pressures
Fluid systems

Two

References: •Transport Phenomena by Bird, Stewart, Lightfoot •Fluid Mechanics and Hydraulic machines by R K Rajput R.K. •http://www.freescale.com/files/sensors/doc/app_note/AN1573.pdf (18 F 10) •http://www.ac.wwu.edu/~vawter/PhysicsNet/Topics/Pressure/Hydro Static.html (18 F 10) SM(15)

## You May Also Find These Documents Helpful

• Good Essays

responsibility in maintaining standards, said Roberts, the faculty co-chair for the Board of Judicial Affairs, in an interview after the panel.) Instead, panelists linked cheating to the social pressure put on students to prize high grades over education and other values, including creativity and imagination. Pressure by parents and schools to achieve top scores has created stress levels among students—beginning as early as elementary school—that are so high that some educators regard it as a health epidemic…

• 673 Words
• 2 Pages
Good Essays
• Good Essays

Pressure Today in our modern society cheating in school is growing at a rapid rate, but who is to blame, is it the school system is it students or is it the teachers. I strongly believe that it is not only the student’s fault but the school systems as well. To begin, cheating among students has rapidly increased. The numbers are crazy; statically 2 out of every 3 kids have cheated on a test, homework, ect. “Cheating in school is rampant and getting worse 64% of students cheated on a test in the…

• 500 Words
• 2 Pages
Good Essays
• Good Essays

According to the essay “Too Much Pressure” by Colleen Wenke, the reason that students cheat on their tests is because they are under too much pressure to get good grades, which is accurately portrayed since cheating is usually seen as one of the only ways to pass tests and that’s what students are being stressed to do. Based on her essay, teachers should be teaching students right from wrong as opposed to pressuring to the extent of making them cheat. This is important to see because it is a way…

• 634 Words
• 3 Pages
Good Essays
• Better Essays

Feature Strategies to improve the prevention of pressure ulcers Judy Elliott describes a project that sought to improve tissue viability during the patient journey from admission to discharge Summary This article outlines the actions taken by one acute trust to implement evidence-based, best practice recommendations for pressure ulcer prevention. Initially, an exploratory study identified specific areas for practice development, particularly improving early risk assessment, intervention and…

• 4242 Words
• 17 Pages
Better Essays
• Powerful Essays

To what extent have pressure groups changed in recent years? A pressure group is an organised group that seeks to influence government policy, public opinions or protect or advance a particular cause or interest. Groups may promote a specific issue and raise it up the political agenda, represent a particular section in society or they may have more general political and ideological objectives in mind when they campaign. In this essay I am going to analyse the significant changes in the nature…

• 1608 Words
• 7 Pages
Powerful Essays
• Good Essays

Peer Pressure What is peer pressure? Adolescents often times deal with pressures from homework, love, money, parents and teachers. However, one of the things that pressures us the most is how to fit in with our peers. We call it peer pressure. Simple enough, it is exactly what it says  pressures from your peers. Peer pressure is when you do something either because they have persuaded you or because all your peers are doing it. Do you remember the last time your parents declined your…

• 1328 Words
• 6 Pages
Good Essays
• Good Essays

Peer pressure Have you ever been forced to do anything ? Have u ever felt that you are in a tight corner because of someone's comment? we all could face situations like that; we all could have faced peer pressure. what is peer pressure? " Peer pressure is when someone or a group of people influences or encourages others to do things they do not want to do or tries to change people’s attitude, or behavior towards something…

• 882 Words
• 4 Pages
Good Essays
• Good Essays

Peer Pressure has been very controversial topic over the years. Today, the media has transformed the issue into a topic that is discussed every day. Many people are sometimes misinformed about topics because the media twist facts enough to make anyone believe what they tell them. The media has gotten the public to believe that peer pressure is all bad and only certain people deal with it, but peer pressure can be used positively or negatively depending on the situation. Peer pressure is when a person…

• 1082 Words
• 5 Pages
Good Essays
• Good Essays

Peer Pressure, Cause and Effect Peer pressure has become a big issue in our modern world. Many people experience it every day and a lot of times it leads to bad decision making. Peer pressure can affect you in the long run and knowing how to say no to certain things can sometimes save your life. There are many causes to peer pressure but the more noticeable one would be just pure excitement. Say that your peers are jumping their bikes off ramps and they ask you to try. You…

• 1092 Words
• 5 Pages
Good Essays
• Good Essays

involved and try to pressure you one way or another it can be even harder. People who are your age, like your classmates, are called peers. When they try to influence how you act, to get you to do something, it's called peer pressure. It's something everyone has to deal with, even adults. Maybe you want to do it, and you just don't have the courage to do it and your friends talk you into it. Peer Pressure can be broken down into two areas, good peer pressure and bad peer pressure. When we think of…

• 863 Words
• 4 Pages
Good Essays