Fluid Mechanics

The study of fluids - liquids and gases. Involves various properties of the fluid, such as velocity, pressure, density and temperature, as functions of space and time.

Absolute or Dynamic Viscosity of Water

Absolute, or dynamic viscosity of water in centipoises for temperatures between 32 - 200^oF

Air - Altitude, Density and Specific Volume

The density and the specific volume of air varies with the elevation above sea level

Air - Temperature, Pressure and Density

Air density for pressures and temperatures ranging from 0 psi to 1000 psi and 30 to 600 deg F

Bernoulli Equation

A statement of the conservation of energy in a form useful for solving problems involving fluids. For a non-viscous, incompressible fluid in steady flow, the sum of pressure, potential and kinetic energies per unit volume is constant at any point

Bulk Modulus and Fluid Elasticity

An introduction to and a definition of the Bulk Modulus Elasticity commonly used to characterize the compressibility of fluids

Capillarity

Capillarity or capillary action is the ability of a narrow tube to draw a liquid upwards against the force of gravity

Carbon Dioxide Concentration in Rooms

The carbon dioxide concentration in rooms may be used to indicate the air quality and the efficiency of the ventilation system

Cauchy Number

An introduction to and a definition of the Cauchy Number

Cavitation - an Introduction

Cavitation occurs in a fluid flow system when the local static pressure is below the vapor pressure.

Cavitations Number

An introduction to and a definition of the Cavitations Number

Center of Gravity and Center of Buoyancy

Center of gravity, center of buoyancy and stability

Chezy Formula

Conduits flow and mean velocity

Colebrook Equation

Calculate friction loss coefficients in pipes, tubes and ducts

Compression and Expansion of Gases

Isothermal and Isentropic processes

DArcy-Weisbach Equation for Pressure and Head Loss

The DArcy-Weisbach formula can be used to calculate pressure or head loss due to friction in ducts, pipes and tubes

Density of a Fluid - Changing Pressure and Temperature

Calculate the density of a fluid when changing pressure and temperature

Density, Specific Weight and Specific Gravity

An introduction and definition of density, specific weight and specific gravity - formulas with examples

Drag Coefficient

The drag coefficient is used to express the drag of an object in moving fluid

Dynamic or Absolute Viscosity Converting Chart

An absolute or dynamic viscosity converting chart for units like Poiseuille - Poise - centiPoise and more

Dynamic Pressure

Dynamic pressure is the component of fluid pressure that represents a fluids kinetic energy

Dynamic Viscosity of some common Liquids

Absolute or Dynamic Viscosity viscosity of some common fluids

Dynamic, Absolute and Kinematic Viscosity

An introduction to dynamic, absolute and kinematic viscosity and how to convert between CentiStokes (cSt), CentiPoises (cP), Saybolt Universal Seconds (SSU), degree Engler and more

Energy and Hydraulic Grade Line

The hydraulic grade and the energy line are graphical forms of the Bernoulli equation

Entrance Length and Developed Flow

The entrance length is the length in a tube or duct until the flow velocity profile is fully developed after obstructions.

Entropy in Compressible Gas Flow

Calculating entropy in compressible gas flow

Equation of Continuity

The Equation of Continuity is a statement of mass conservation

Equation of Mechanical Energy

The equation of mechanical energy in terms of Energy per Unit Mass, Energy per Unit Volume and Energy per Unit Weight involving head

Equations in Fluid Mechanics

Common fluid mechanics equations - Bernoulli, conservation of energy, conservation of mass, pressure, Navier-Stokes, ideal gas law, Euler equations, Laplace equations, Darcy-Weisbach Equation and more

Equivalent Diameter

Convert rectangular and oval duct geometry to a equivalent circular diameter - online calculator with imperial and SI-units

Euler equations

The behavior of ideal compressible gas can be described by the Euler equations

Euler Number

An introduction and definition of the Euler Number in fluid mechanics

Flow Coefficient Cv and Flow Factor Kv

Comparing the flow coefficient C_v with the flow factor K_v

Fluid Flowmeters

Flow metering basics. Introduction to Orifice, Venturi, Flow Nozzles, Pitot Tubes, Target, Variable Area, Positive Displacement, Turbine, Vortex, Electromagnetic, Ultrasonic Doppler, Ultrasonic Time-of-travel, Mass Coriolis, Mass Thermal, Weir V-notch, Flume Parshall and Sluice Gate flow meters

Fluid Mechanics and Conservation of Mass

The law of conservation of mass states that mass can neither be created or destroyed

Fluid Mechanics Imperial and SI Dimensions and Units

Imperial (USCS) and SI dimensions and units terminology

Fluids - Kinematic Viscosities

Kinematic viscosities of some common fluids - motor oil, diesel fuel, peanut oil and many more

Friction Coefficient at Laminar Flow

Laminar flow and friction coefficients

Froude Number

An introduction to and a definition of the Froude Number

Gas Mixture Properties

Special care must be taken for gas mixtures when using the ideal gas law, calculating the mass, the individual gas constant or the density

Hazen-Williams Coefficients

Hazen-Williams factor for some common piping materials

Hazen-Williams Equation - calculating Friction Head Loss in Water Pipes

Friction head loss (ft H2O per 100 ft pipe) in water pipes can be obtained by using the empirical Hazen-Williams equation

Heating Systems - Pressure Loss Diagram Steel Pipes

Pressure loss diagram hot water heating systems - steel pipes and tubes

Hydraulic Diameter

Hydraulic diameter of ducts and tubes

Ideal Gas Law

In perfect or ideal gas the change in density is directly related to the change of temperature and pressure as expressed by the Ideal Gas Law

Isentropic Flow

Constant entropy flow is called isentropic flow

Kinematic Conversion Diagram

Convert diagram between Centistokes, Saybolt and Redwood seconds

Kv Diagram Water Valves

Kv diagram for modulating water valves

Laminar, Transitional or Turbulent Flow?

It is important to know if the fluid flow is laminar, transitional or turbulent when calculating heat transfer or pressure and head loss.

Laplace Equation

Laplace equation are important in fluid dynamics describing the behavior of gravitational and fluid potentials

Mach Number

An introduction to and a definition of the Mach Number

Major loss in Ducts, Tubes and Pipes

Major loss - head loss or pressure loss - due to friction in ducts, pipes and tubes

Major Loss Online Calculator for Fluid Flow using Darcy-Weisbach Friction Loss Equation

An online major loss calculator using Darcy-Weisbach friction loss equation. Energy (or head) loss is expressed in length units

Manning Formula for Gravity Flow

Manning equation for calculating gravity flow in open channels

Mannings Roughness Coefficient

Mannings roughness coefficient values for some common materials

Mass and Weight

What is weight and what is mass? An explanation of the difference between weight and mass

Minor Loss Coefficients for Air Duct Components

Minor loss - pressure or head loss - coefficients for air duct distribution systems components

Minor Loss Coefficients in Pipes and Tubes Components

Minor loss coefficients for common used components in pipe and tube systems

Minor Loss in Pipe or Duct Components

Minor loss, pressure or head loss in pipe, tube and duct system components

Mixtures, Solutions and Suspensions

The difference between mixtures, solutions and suspensions

Moody Diagram

A very nice Moody Diagram that can be used to estimate friction coefficients

Moody Friction Flow Factor

Online Moody friction flow factor calculator - used in the Darcy-Weisbach major loss equation

Navier-Stokes Equations

The Navier-Stokes equations are the fundamental partial differentials equations describing incompressible fluid flow

Nozzles

Gas flow through nozzles - sonic chokes

Oil Viscosity Conversion Factors

Convert between common oil viscosity units

Online Absolute or Dynamic Viscosity Converter

Convert between dynamic or absolute viscosity units - Poiseuille, Poise, centPoise and more

Online Kinematic Viscosity Calculator

Convert between different kinematic viscosity units - centistokes, poise, lentor and more

Online Pressure Units Converter

Convert between common pressure units like Pa, bar, atmosphere, pound square feet, psi and more - with converting tables

Orifice, Nozzle and Venturi Flow Rate Meters

The orifice, nozzle and venturi flow rate meters use the Bernoulli Equation to calculate the fluid flow rate by using the pressure difference between an obstruction in the flow.

Pascals Laws

Pascals laws relates to the pressure in a fluid

Pipe Velocities

Calculate fluid flow and pipe velocity

Prandtl Number

The Prandtl Number is a dimensionless number approximating the ratio of momentum diffusivity and thermal diffusivity

Pressure

An introduction to pressure - the definition and presentation of common units as psi and Pa and the relationship between them - online pressure units converter

Pressure-Gradient Diagrams

A pressure-gradient diagram is a graphical presentation of the static pressure throughout a fluid flow system

Pump Affinity Laws

Turbo machines affinity laws are used to calculate volume capacity, head or power consumption, when speed - rpm, or wheel diameters are changed for centrifugal pumps

Pumps, Compressors, Blowers and Fans

Comparing pumps, compressors, blowers and fans

Ratio of Specific Heat

The heat capacity of a gas in a constant pressure process - to the heat capacity of a gas in a constant volume process

Reynolds Number

An introduction and definition of the dimensionless Reynolds Number - with online calculators

Solubility

Amount of a solute that can be dissolved in a solvent

Specific Work of Turbo Machines - Pumps, Compressors and Fans

Specific work of pumps, fans, compressors and turbines

Speed of Sound Formulas

Calculation formulas for velocity of sound in gas, fluid or solid

Static Pressure and Pressure Head in Fluids

Static pressure and pressure head in fluids

Strouhal Number

An introduction to and a definition of the Strouhal Number

Surface Tension

Surface tension of some common liquids like water, mercury, oils and more

Technical Terms in Fluid Mechanics

Some of the most common used technical terms used in fluid mechanics

The Individual and Universal Gas Constant

The Individual and Universal Gas Constant in fluid mechanics and thermodynamics

Total Pressure or Head Loss in Pipe or Duct Systems

Major and minor loss in pipe, tubes and duct systems

U-Tube Manometer

The inclined and vertical u-tube manometers are inexpensive and common in differential pressure measurements of flow meters like pitot tubes, orifices and nozzles