# Fluid Mechanics (ME 3111 & ME 3121)

In this course, students learn how to analyze fluids at rest (fluid statics) and fluids in motion (fluid dynamics). Fluid mechanics topics are distributed between ME 3111 (Fluid Mechanics) and ME 3121 (Intermediate Thermal-Fluids Engineering).

### Demonstration videos (links to non-CPP content)

Concept: Comparing the viscosity of various liquids
Description: Liquids with higher viscosities will flow slower than fluids with lower viscosities, assuming the flow conditions of the liquids are the same. The video also presents a molecular picture of viscosity.

Concept: Dilitant/shear-thickening fluid #1
Description: For some non-Newtonian fluids, the viscosity increases with increasing shear stress. In the video, a small kiddie pool is filled with a shear-thickening fluid and people are able to run on its surface without sinking. Notice that the fluid almost behaves like rubber when strong shear stresses are applied, but flows readily when when weak shear stresses are applied.

Concept: Dilitant/shear-thickening fluid #2
Description: A larger pool is filled with a shear-thickening fluid. People are able to walk, dance, and bike over the surface, but sink when standing in place.

Concept: Dilitant/shear-thickening fluid #3
Description: A shear-thickening fluid allows a slow-moving ruler to easily penetrate its surface, but can resist violent blows from a sledgehammer.

Concept: Surface tension
Description: Although aluminum has a greater density than water, it is possible to float aluminum coins on the surface of a body of water because the surface tension of water provides a sufficiently large upward force. When liquid soap is added to water, the surface tension of the resulting water/soap mixture is lowered and it is now insufficient to prevent the aluminum coins from sinking. Materials that lower surface tension are called "surfactants."

### Concept/Derivation videos

5 - Archimedes' principle & buoyancy

### Demonstration videos (links to non-CPP content)

Concept: Existence of atmospheric pressure #1
Description: A 55 gallon drum has a saturated liquid-vapor mixture. During heating, the contents are kept near atmospheric pressure since the cap is off. After the heating is stopped, the contents are sealed near atmospheric pressure. As the drum is cooled, some of the vapor condenses to liquid which lowers the internal pressure until the drum is crushed by atmospheric pressure.

Concept: Existence of atmospheric pressure #2
Description: Similar to the last video, an aluminum can initially has a saturated liquid-vapor mixture. As the can is cooled, some of the vapor condenses to liquid which lowers the internal pressure until it is crushed by atmospheric pressure.

Concept: Existence of atmospheric pressure #3
Description: A large storage tanker was not vented properly and the pressure inside the tanker became too low. Atmospheric pressure is sufficient to crush the large tanker.

Concept: Buoyant force of a liquid
Description: The density of liquid mercury is so high that it exerts a buoyant force large enough for iron cannonballs to float in it.

Concept: Buoyant force of a gas
Description: The density of gaseous sulfur hexaflouride is so high that it exerts a buoyant force large enough for air-filled balloons to float in it. Also notice that the gas does not rapidly dissapate into the atmosphere due to its relatively high density.

Concept: Rigid body rotation
Description: A tank containing water rotates at a certain angular velocity. The water's momentum attempts to carry it away toward the walls, but is kept in check by the pressure of the fluid above it. After the initial sloshing dies down, the water and tank rotate at the same rate and appear as a rigid body, with the free surface forming a paraboloid. The pressure is atmospheric over the entire free surface and the lines of constant pressure (isobars) are parabolic as well.

### Demonstration videos (links to non-CPP content)

Concept: Transition from laminar to turbulent flow
Description: At lower flow rates, laminar flow is observed as the dye streamline remains unchanged as it travels down the pipe. At higher flow rates, turbulent outburst are observed, followed by turbulent flow.

### Demonstration videos (links to non-CPP content)

Note: Dr. Biddle's ME 311 (Fluid Mechanics I) and ME 312 (Fluid Mechanics II) lectures were recorded in the quarter system. These topics are now distributed between ME 3111 (Fluid Mechanics) and ME 3121 (Intermediate Thermal-Fluids Engineering). Lectures 1-18 were recorded for ME 311 in Fall 2014 and lectures 19-34 were recorded for ME 312 in Winter 2018.

In the semester system, lectures 1-25 are covered in ME 3111, while lectures 26-34 are covered in ME 3121.

ME311 - Fluid Mechanics I

ME312 - Fluid Mechanics II

Syllabus for ME 312, Winter 2018

Lecture 19 - Pipes in series
Lecture 20 - Parallel and Branching Pipes
Lecture 21 - Centrifugal Pump Characteristics
Lecture 22 - Series and Parallel Pumps
Lecture 23 - Dimensional Analysis
Lecture 24 - Similitude
Lecture 25 - Dimensionless Pump Performance
Lecture 26 - Introduction to Compressible Flow
Lecture 27 - Compressible Isentropic Flow
Lecture 28 - Converging Nozzles
Lecture 29 - Shock Waves
Lecture 30 - Converging-Diverging Nozzles
Lecture 31 - Laminar Boundary Layer on a Flat Plate
Lecture 32 - Turbulent Boundary Layer on a Flat Plate
Lecture 33 - Drag Forces on Blunt Bodies
Lecture 34 - Examples of Blunt Body Drag

Interview with Dr. John Biddle