Fluid Mechanics Lectures 2nd year/1st semister/ /Al-Mustansiriyah unv

Slides:

Advertisements

Similar presentations

Fluid mechanics. Pressure at depth In a cylindrical column of water, as in any cylinder the volume is the height x cross sectional area The density of.

Advertisements

Archimedes’ Principle An object immersed in a liquid has an upward buoyant force equal to the weight of the liquid displaced by the object. An object will.

The pressure is on Which is the best design for a dam? Explain your answer. Which dam is more likely to break? Explain your answer.

Static Fluids Fluids are substances, such as liquids and gases, that have no rigidity. A fluid lacks a fixed shape and assumes the shape of its container.

Ch. 19 Liquids. Molecules flow, moving/flowing over one another. Takes the shape of its container.

Physics 102 Part II Thermal Physics Moza M. Al-Rabban Professor of Physics Fluids (2)

Floating and Sinking.

The tendency or ability of an object to float.

Sect. 14.4: Buoyant Forces Archimedes’ Principle

Static Fluids Fluids are substances, such as liquids and gases, that have no rigidity. A fluid lacks a fixed shape and assumes the shape of its container.

The lifting force of the water SWAG. In science, buoyancy is an upward force exerted by a fluid that opposes the weight of an immersed object. In a column.

Fluid Mechanics Chapter 10.

Chapter 3 Section 2 Buoyancy and Density

Faculty of Engineering

Sect. 10-7: Buoyancy/Archimedes Principle Experimental facts: –Objects submerged (or partially submerged) in a fluid APPEAR to “weigh” less than in air.

PHYSICS 103: Lecture 17 Fluids  Gases (Air)  Liquids  Archimedes Principle Agenda for Today: Note: The next several lectures will not follow textbook.

A fluid is a state of matter in which the particles are free to move around one another. No definite shape exists. The term “fluid” encompasses liquids.

Fluid Mechanics - Hydrostatics AP Physics 2. States of Matter Before we begin to understand the nature of a Fluid we must understand the nature of all.

Ch. 11 Forces in Fluids. Pressure Pressure-force per unit area on a surface Unit of measurement: pascal (Pa): 1 N/m 2 A fluid is any substance that can.

Plan for Today (AP Physics 2) Demonstrations, questions, and lecture on fluids.

PHYSICS 103: Lecture 18 Archimedes Principle Example Problems Agenda for Today:

Density and Buoyancy. Float? Whether an object will float or not is dependent on the density of the object and the density of the fluid.

Floating and Sinking.  Density is a measure of how closely packed the atoms in a substance are  Density is a physical property  All matter has measurable.

Physics 1B03summer-Lecture 12 1 Fluid Mechanics Pressure Buoyancy.

The fun never stops.... Liquids and Gases can exert forces. – Examples: waves crashing, wind Liquids and Gases can exert forces. – Examples: waves crashing,

Fluid Mechanics Chapter 8. Mass Density The concentration of matter of an object, measured as the mass per unit volume of a substance. Represented by.

Floating and Sinking. Buoyancy When you pick up an object underwater it seems much lighter due to the upward force that water and other fluids exert known.

Buoyant Forces Chapter 3 Section 2.

Chapter 19 Liquids.

Hydrostatics Lesson 6 © nitatravels. Fluids are Everywhere  Liquids or Gasses  Air is a fluid!!!  Typically take the shape of their container.

Liquids Definite volume but no definite shape!. Liquids Pressure Buoyancy Archimedes’ Principle Density Effects Pascal’s Principle.

Density. (a) define the term density What is density? Density is defined as mass per unit volume.mass Density is defined as mass per unit volume.mass.

Density and Buoyancy Review 1-20 study notes. 1. Density =

Chapter 10.4 Learning Goals

Forces in Fluids Chapter 13. Fluid Pressure  Section 13-1.

CONCEPTUAL PHYSICS Liquids.

1 Bell Ringer What word should we think of when we think of pressure? 2. What is the formula for pressure? 3. What SI unit measures pressure?

Floating and Sinking Whatever floats your boat!. Warm-up 1. Observe the two beakers on the front table and record your observations. 2. Predict- will.

Chapter 11 Section 2: Floating and sinking Key concepts: what is the effect of the buoyant force? How can you use density to determine whether an object.

Dr. Jie Zou PHY 1151G Department of Physics1 Chapter 15 Fluids (Continued)

Fluid Mechanics - Hydrostatics AP Physics B. States of Matter Before we begin to understand the nature of a Fluid we must understand the nature of all.

Liquids Physics principles of liquids Density The density, ρ (rho), of an object is defined as the mass per unit volume ρ ≡ρ ≡ Units are grams/cm 3 or.

Chapter 10 Fluids Pressure in Fluids Pressure is defined as the force per unit area. Pressure is a scalar; the units of pressure in the SI system.

Consider a block submerged in water, suspended from a string. – The pressure of the water pushes on the block from all sides. – Because the pressure increases.

Chapter 9 Forces influence the motion and properties of fluids.

Lecture 14.1 Fluids. Does lead float? Schedule today Fluid Statics Density Pascal's Principle Archimedes Principle Exam Solutions Curve.

Floating and Sinking.

3-3 Floating & Sinking.

Topic: Floating and Sinking

L 13 Fluids [2]: Statics  fluids at rest

Fluid Mechanics Presentation on FLUID STATICS BY Group:

Density and Buoyancy Chapter 11.2 Page 424.

Chapter 12 Section 2.

How could we explain the relationship between density and buoyancy?

Section 2 – pg 424 Floating and Sinking

Pressure in Fluid Systems

Chapter 19: Liquids.

3.2 Pressure and the Buoyant Force

Floating and Sinking.

Floating and Sinking Chapter 11 Section 2.

Physical Science Forces in Fluids.

Fluid Mechanics – Buoyancy

BUOYANCY AND ARCHIMEDES' PRINCIPLE

Chapter 12 Section 2.

Fluid Mechanics Lectures 2nd year/1st semister/ /Al-Mustansiriyah unv

Whatever floats your boat!

Why does an ice cube float in water?

Fluid Mechanics Lectures 2nd year/2nd semister/ /Al-Mustansiriyah unv

Presentation transcript:

Fluid Mechanics Lectures 2nd year/1st semister/2018-2019/Al-Mustansiriyah unv./College of engineering/Highway &Transportation Dep.Lec.5

. Buoyancy(Archimedes principle) An important aspect of hydrostatic pressure deals with determining the net force that is exerted on an entire body that is either completely submerged or floating in a partially submerged position. In case of either completely submerged or floating there is a net upward pressure acting on the body. This force called the buoyancy force, occurs because pressure increase with depth. Thus the pressure acting upward on a bottom surface area is greater than the pressure acting downward. On the other hand the net horizontal pressure force on a completely submerged or floating body equals zero.

. Completely submerged body The weight W of the submerged body occupying the volume IJKLI. The vertical force Ftop acting downward on the top surface of the body that equals the weight of the fluid in the volume HILKMH: Ftop =γfluid*Vfluid 3-Thevertical force Fbottom acting upward on the surface of the body that equals the weight of the fluid that would occupy the volume HIJKMH if the body were not present: Fbottom=γfluid *Vfluid Since Fbottom is greater than Ftop there is a net upward pressure force (Fbottom-Ftop) acting on the submerged body. Since Fbottom-Ftop) equals the weight of fluid having a volume equal to volume of the body: FB=γfluid*Vfluid. FB is called buoyancy force. .

Apparent body weight=γbody*Vbody-γair*Vbody. When a person gets weighed the recorded weight called apparent weight really equals the actual weight minus the weight of the atmospheric air displaced by the personꞌs body. Thus the measured weight of a person equals the weight of the person in a perfect vacuum minus the weight of atmospheric air displaced by the person: Apparent body weight=γbody*Vbody-γair*Vbody.

Examples Ex.1:The weight of a person is 180 lb where the specific weight of the atmospheric air is 0.0765 lb/ft3. If the persons total volume is 2.95 ft3. What is the persons actual weight and average specific weight? Apparent weight=actual W-γair*Vperson 180=actual W-(0.0765)*(2.95) Actual W=180.23 lb. Persons average density =actual W/Vol. =180.23/2.95 =61.1lb/ft3 (human beings have an average specific weight of about 61 lb/ft3 and thus can theoretically float in water because the specific weight of water is 62.4 lb/ft3)

Ex.2: Using pressure height relation(P=γh) show that the buoyancy force a completely submerged circular cylinder equals the weight of the liquid displaced by the cylinder FB=F2-F1=P2A-P1A FB=(Patm+γluquid*h2)A-(Patm+γ liquid*h1)A FB= γluquid(h2-h1)A FB= γluquid V cyl.= weight of the displaced liquid. ) -

Ex.3:A 6 in cube completely submerged in water is balanced by a 10lb weight on the beam scale, determine the specific gravity of the cube material T(tension)*1=10 *1.5 T=15lb T+FB-W=0 FB=γ water *V disp.water=γ water *V cube =62.4*63*1/1728=7.8 lb W=T+FB =15+7.8=22.8 lb γ cube=W cube/V cube =22.8/63*(1/1728)=182 lb/ft3 S.G=γ cube/ γ water=182/62.4=2.92 .

Thanks