MODULE 3 SET B Flashcards by Shandy Raene Lagubana

study of fluids in motion

FLUID MECHANICS

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a subdiscipline of fluid mechanics that describes the flow of fluids

FLUID DYNAMICS

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SUBDISCIPLINES OF FLUID DYNAMICS

AERODYNAMICS
HYDRODYNAMICS

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path of every particle that passes a particular point moves along exactly the same smooth path followed by previous paticles passing point

STREAMLINE OR LAMINAR

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TRUE OR FALSE

The streamline at any point coincides with the direction of the velocity of the fluid at that point

TRUE

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it tends to slow the flow of fluid

FRICTION

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The fluid closest to the vessel walls moves the —————–

slowest

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The fluid in the center of the vessel moves the ——–

fastest

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a type of flow where the velocity of the fluid changes layer by layer, or according to the distance from the vessel walls, is called ———–

LAMINAR FLOW

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A fluid flow in which the velocity at a given point varies erratically in magnitude and direction

TURBULENT FLOW

thanks, Via

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Irregular motions of the fluid, called ———-, are characteritic in turbulent flow.

EDDY CURRENTS

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Regions of fluid move in irregular, colliding paths, resulting in mixing and swirling.

TURBULENT FLOW

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The volume of fluid passing by a given location through an area during a period of time is called

Q, volume flow rate

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FORMULA FOR VOLUME FLOW RATE

Q = Av

A = cross-sectiobal area
v= velocity

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The product of the cross-sectional area of the tube and the fluid speed at that cross-section is a constant.

EQUATION OF CONTINUITY

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A constricted area = ——- speed

high speed

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larger diameter = ——– speed

low speed

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TRUE OR FALSE

The volume of the fluid that enters one end of the tube in a given time interval equals the volume of the fluid leaving the tube in the same interval.

TRUE

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EQUATION CONTINUITY FORMULA

A1V1=A2V2;
Q1=Q2

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SAMPLE PROBLEM

The blood flow speed is 40cm/s in an aorta with a cross-sectional area of 2.0 cm2. Assume that the aorta branches to form a large number of capillaries with a combined cross-sectional area of 3.0 x 10^3 cm2. What is the flow speed in the capillaries?

Vc = 0.027 cm/s

GIVEN: A_a = 2cm^2
v_a= 40cm/s
A_c = 3.0 x 10^3 cm2

He is a Swiss physicist who derived an expression that relates the pressure of a fluid to its speed and elevation in 1738.

DANIEL BERNOULLI

For an incompressible, frictionless fluid, the combination of pressure and the sum of kinetic and potential energy densities is constant not only over time, but also along a streamline.

BERNOULLI’S PRINCIPLE

Mathematically, the Bernoulli’s equation is expressed as

p + pgh + (1/2)pv^2

P = PE due to pressure
pgh = PE due to gravity
(1/2) pv^2 = KE

TRUE OR FALSE

In BERNOULLI’S Principle, fluid flows at a constant depth or height, h1=h2.

TRUE

APPLIES TO SMALL VOLUME OF FLUIDS

# TRUE OR FALSE AS THE VELOCITY OF A FLUID INCREASES, ITS KINETIC ENERGY ALSO INCREASES.

TRUE

# TRUE OR FALSE Pressure drops as speed increases in a moving fluid.

TRUE

# TRUE OR FALSE A high diameter indicates a high pressure.

TRUE

# TRUE OR FALSE A high pressure indicates a high speed.

FALSE | Pressure is inversely proportinal to velocity

# TRUE OR FALSE A smaller diameter pertains to a smaller pressure, but a high velocity.

TRUE

# PRACTICE PROBLEM: The volumetric flow rate of blood in a person at rest is about 5.0 L per minute. If the aorta (the central artery carrying the blood from the heart) has a diameter of 2.0 cm, what is the kinetic energy of blood flowing through the aorta? pblood = 1060 kg/m^3.

37.30 J/m^3

refers to the internal friction of a fluid

VISCOSITY

The fluid flows through the tube because of -----------.

PRESSURE DIFFERENCE

The rate of flow (volume per unit time) depends on the --------------------.

PRESSURE DIFFERENCE

The greater the pressure differejntial between two points, the -------------- the flow rate.

the greater the flow rate

A French scientist who derived the law of resistance in an attempt to understand the flow of blood through the body

J. L. POISEUILLE

It states that the rate of flow should increase if the pressure difference across the tube or the tube radius increases.

POISEUILLE'S LAW FOR RESISTANCE

# TRUE OR FALSE The flow rate decrease as the viscosity of the fluid or the length of the tube increases.

TRUE

# TRUE OR FALSE Q = (P2 - P1)/L

TRUE | Q directly proportional to pressure diffrnce;inversely proportional to L

# TRUE OR FALSE The viscosity of blood increases as the number of red blood cells increases.

TRUE

# TRUE OR FALSE In a case where flow rate is constant, viscous friction reduces the pressure.

TRUE

# TRUE OR FALSE Pressure drop is inversely proportional to the radius to the fourth power.

TRUE | A small change in radius = big change to pressure drop

# PRACTICE PROBLEM The volumetric flow rate of blood in a person at rest is about 5L per minute. The beginning of the aorta (the path closest to the heart) has a diameter of 3cm, but the end of the aorta in the lower abdomen has a diameter of only 1.75 cm. a. what is the flow rate of blood at the beginning of the aorta in m/s? b. what is the flow rate of blood at the end of the aorta in the lower abdomen in m/s? c. how much faster is the blood travelling at the end of the aorta than it is at the beginning?

a. 0.118 m/s b. 0.346 m/s c. 0.228 m/s

# PRACTICE PROBLEM Water flows through a tube with a diameter of 2m at a rate of 800 kg/s. What is the velocity of water?

0.25m/s | https://www.varsitytutors.com/ap_physics_2-help/flow-rate

# PRACTICE PROBLEM Suppose that water flows from a pipe with a diameter of 1m into another pipe of diameter 0.5m. If the speed of water in the first pipe is 5m/s, what is the speed in the second pipe?

20 m/s | https://www.varsitytutors.com/ap_physics_2-help/flow-rate

# PRACTICE PROBLEM A diameter garden hose with a diameter of 3cm sprays water travels through a hose at 1m/s. At the end of the garden hose, the diameter reduces to 2cm. What is the speed of the water coming out at the end?

2.25 m/s | https://www.varsitytutors.com/ap_physics_2-help/flow-rate

# PRACTICE PROBLEM An incompressible fluid flows through a pipe. At location 1 along the pipe, the volume flow rate is 10m^3/s. At location 2 along the pipe, the area halves. What is the volume flow rate at location 2?

10m^3/s | https://www.varsitytutors.com/ap_physics_2-help/flow-rate

# PRACTICE PROBLEM What is the volumetric flow rate of ethanol flowing through a square pipe with sidelength 4m? The velocity of the ethanol is 7m/s.

112 m^3/s | https://www.varsitytutors.com/ap_physics_2-help/flow-rate

# PRACTICE PROBLEM A pipe narrows from a 30m diameter to a 15m diameter. What is the velocity of the fluid when it exits the pipe (at the 15m end) if it entered the pipe at 15m/s?

60 m/s | https://www.varsitytutors.com/ap_physics_2-help/flow-rate