week 2 fluids

Question 1

what is a fluid

Answer 1

fluid has the ability to flow
can be a liquid or a gas.
gravity causes fluids to flow.
assume shape of the container

Question 2

what is hydrostatics

Answer 2

the study of fluids that are NOT moving

Question 3

fluids that are static what are two useful properties?

Answer 3

density and pressure

Question 4

hydrodynamics

Answer 4

is the study of fluid in motion.

Question 5

pressure formula

Answer 5

p= F/A 
F= force
A= area

Question 6

Pressure is inversely proportional to the area.

t/f?

Answer 6

true If you double the area (or diameter), you will decrease pressure by 4.

Question 7

Imagine a beaker filled with water
How much pressure does the water exert on the bottom of the beaker?
The beaker measures 10 cm in diameter and the height of the water is 20 cm.

Answer 7

Only the weight of atmosphere is pushing down on the top surface of the water. Both the weight of the atmosphere and the weight of the water are pushing down on the bottom of the beaker. Obviously, the force pushing down on the bottom of our beaker is larger than theforce pushing down on the top of the water.

Question 8

Pressure at the Same Depth

Answer 8

At the same depth in a fluid, the fluid exerts the same pressure and in all directions

Question 9

is Pressure Is Independent of Container Shape

Answer 9

yes

Question 10

Pascal’s Principle is?

Answer 10

The pressure applied to a confined fluid increases the pressure throughout the fluid by the same amount.
Example, if you increase the pressure on top of a confined fluid by 5 Pa, the pressure everywhere in the fluid goes up by 5 Pa

Question 11

You’re applying a pressure of 3 psi on the plunger of a syringe with a plugged needle.
How does the pressure in the barrel compare to the pressure in the needle?

Answer 11

they are the same pressure.

Question 12

Buoyancy

Answer 12

All fluids exert a buoyant force on objects immersed in them.

Question 13

Archimedes Principles

Answer 13

An object immersed either totally or partially in a fluid feels a buoyant force equal to the weight of the fluid displaced.

Question 14

If the density of the object is greater than the density of the fluid, it will what?

also vice versa

Answer 14

sink,

If the object sinks, the buoyant force is less than the true weight of the object.

Question 15

Hydrometers

Answer 15

A hydrometer is a very simple device used to measure the specific gravity of liquids.

A hydrometer will sink until it displaces an amount of fluid exactly equal to its weight. If the fluid is dense, it will displace only a small amount of fluid and thus not sink very deep. If the density of the fluid is not very high, the hydrometer will sink deeper.

Question 16

Hydrodynamics is the study of what kind of fluids?

Answer 16

moving fluids

Question 17

Two types of flow are?

Answer 17

Laminar flow-unchanging flow pattern, smooth and orderly.
Turbulent flow-continuously varying pattern of flow, abruptly changing and chaotic.

In anesthesia we strive for laminar flow

Question 18

Flow Rate is

Answer 18

The volume of fluid passing a particular point (e.g., the black line) per unit time.

Think about oxygen for a patient. We deliver a flow rate i.e. 3 liters/min.

Question 19

Speed and Diameter: narrowing causes what to happen to speed?
slide 18

Answer 19

increases tremendously.
The flow rate remains the same.

if a patient has a larger tube you can have slower flows easier to ventilate
small tube you need higher flows. for more speed.

Question 20

Bernoulli’s Principle is?

Answer 20

As the speed of a fluid increases, the pressure exerted by the fluid decreases.

This phenomenon is called theBernoulli effect

The Bernoulli effect provides the lift for airplanes and is why shower curtains get sucked toward you when you first turn on the shower. It also provides the basis for a Venturi flowmeter.

increase in speed will decrease the pressure of a fluid

Question 21

Venturi Tube Flowmeter measures what

Answer 21

measure fluid speeds in pipes. and prevents turbulance

Question 22

Venturi Tube Flowmeter is used for what

Answer 22

administering an albuterol nebulizer

Question 23

Viscosity

Answer 23

Viscosity is a measure of a fluid’s resistance to flow.

Fluids with high viscosity (honey) do not flow very readily, while fluids with low viscosity (water) flow more easily.

Question 24

The closer a molecule is to a wall, the slower it moves

T/F

Answer 24

true

Question 25

Laminar Flow

Answer 25

When a fluid streams through a tube, the particles comprising the fluid may move along lines parallel to the walls of the tube.

Question 26

Poiseuille’s Law applies to what

Answer 26

Poiseuille’s equation applies to laminar flow only.

radius and length are the two most important things

Question 27

Poiseulle determined that the laminar flow rate of an incompressible fluid along a pipe is proportional to

Answer 27

the fourth power of the pipe’s radius.

Question 28

Poiseuille’s equation yields three possible ways to increase the fluid flow rate through a catheter or needle.

Answer 28

First and foremost, increasing the pressure differential (P1−P2) across the catheter or needle can increase the flow rate.
Raise iv bag height. Add a pressure bag to IV
Use a larger gauge IV catheter.
Or a shorter length catheter.

Question 29

Reynold’s Number is ?

Answer 29

Reynolds’ numberand is the measure of the tendency for turbulence to occur
when Reynolds’ number rises above approximately 2000, turbulence will usually occur even in a straight, smooth vessel.

laminar flow turns turbulent after 2000 ex in the ventricle into the aorta

Question 30

For a given liquid and tube there is a critical flow rate above which the flow will become turbulent.

Answer 30

Reynolds number is less than approximately 2,000 will typically have laminar flow, while Reynolds numbers greater than 3,000 will result in turbulent flow. When the Reynolds number is between these two values, the fluid flow will be unstable, and the flow can transition between laminar and turbulent flow.