Water Properties and Fluid Mechanics Study Notes
Emerging Issues in Water and Hydrolysis
Recent Issues:
Attack on Iran's desalination facilities by the USA.
Iran's previous methods of desalination:
Utilization of boiling water to achieve distillation, a traditional method.
Collecting distilled water after boiling saltwater.
Current Technologies in Water Treatment
Transition from traditional boiling methods to modern desalination systems.
Efficient use of seawater as a resource.
Leading company in water technology: Doosan Heavy Industries.
Course Structure Overview
Follow the textbook chapters through discussions.
Focused on the general properties of water in the upcoming lecture.
Hydrostatics and Fluid Mechanics
Definition of Hydrostatics:
Study of fluids at rest.
Important keywords: Water and Mechanical Properties.
Mechanics Defined
Meaning of Mechanics:
Study of forces acting on fluids.
Key forces acting on stationary water: Gravity.
Example: A cup of water experiencing gravitational forces on its base.
Stationary vs. Flowing Water
Forces acting on flowing water systems:
Key types: Rivers and pipes.
Characteristics of flowing water under pressure.
Key Concepts in Fluid Dynamics
Major Forces:
Gravity acting on stationary water.
Pressure affecting flowing water in piping systems.
Fundamental Terms and Differences
Two major forces in our study:
Gravitational force on stationary water.
Pressure-related forces on flowing water.
Key Differentiating Factors:
Fluid mechanics vs. Hydraulic engineering:
Fluid mechanics approaches problems using
Bernoulli’s and Navier-Stokes equations for theoretical analysis.
Hydraulic engineering focuses on practical application using approximate solutions.
Water Properties
Viscosity of water:
While water has viscosity, it’s often assumed negligible for simplifications in calculation.
General assumption of incompressibility for practical engineering calculations.
Importance of Non-compressibility in Fluid Dynamics
Assumption: Water is incompressible to facilitate easier calculations in hydraulic problems.
Physical Properties of Water
Characteristics of water:
Viscosity and compressibility contrasts:
Common assumption: Water behaves as an incompressible fluid under typical conditions.
Water pressure variances and forces:
Calculating forces exerted on dam walls, or other structures with water.
Example Problems and Forces Distribution
Understanding pressures exerted by water in structures is pivotal.
Example:
If a dam wall is inclined, calculate the forces acting upon it based on the water level and wall angle.
Fundamental Equations and Terms
Pressure equations in hydraulics:
Differentiate between small pressure ($p$) and large pressure ($P$).
Stress and Strain Relationships in Materials
Key definitions:
Tensile strength: resistance to being pulled apart.
Compressive strength: resistance to being compressed.
Shear stress and its applications in fluid mechanics.
Application in Engineering Problems
Concepts applied to engineering scenarios, e.g., assessing structural strength of dams, pipes, etc.
Units of Measurement and Calculation Basics
Importance of dimensional analysis in fluid mechanics.
Define relevant units:
SI units for mass, force, and pressure.
Considerations of CGS and MKS systems in problems.
Calculating the Effects of Pressure and Temperature
Density of water changes under different temperatures:
Impact of temperature on density (e.g., 1 g/cm³ at 4°C dropping to 0.958 g/cm³ at 100°C).
Compressibility of Water
Water's compressibility is very low, which justifies treating it as incompressible for most engineering calculations.
Theoretical applications and boundaries.
Surface Tension and its Consequences
Surface tension principles as applied in fluid situations.
Exploration of forces acting at the surface.
Cohesion and Adhesion Effects
Behavior of water in tubes and capillaries:
Capillary action phenomena explained through molecular adhesion and cohesive properties.
Practical Applications and Assignment Information
Upcoming assignments focusing on the calculations derived from this lecture.
Structure for completing and submitting assignments for grading in the course.
Emphasizing file submission formats and deadlines.
Summary of Key Learning Outcomes
Understanding of hydrostatics, fluid mechanics principles, pressure, and associated calculations is crucial for future applications in engineering