Fluids Flashcards
Fluid dynamics:
Flow type
Reynolds number determines flow type.
Laminar flow occurs at low Reynolds number and turbulent flow occurs at high Reynolds numbers.
Turbulent flow is favored over laminar flow under conditions of high velocity and low viscosity.
Fluid dynamics:
Equation for flow rate
Fluid dynamics:
Describes rate of laminar flow
Pressure gradient is inversely proportional to the radius^4 and directly proportional to length and viscosity of tubing
Poiseuille’s law
Fluid dynamics:
Poiseuille’s law formula
Fluid dynamics:
Continuity equation
Fluid dynamics:
Bernoulli’s equation
Fluid dynamics:
Draw a visual representation of Bernoulli’s equation
Fluid dynamics:
Venturi effect
Fluid passing through a constricted area will increase in velocity and decrease in static pressure.
Equation for pressure
Pressure:
Equation for pressure in a fluid
Pressure:
Equation for pressure in a gauge
Pressure:
Atmospheric pressure conversions
1 atm = 1 Bar = 101 kPa = 760 mm Hg = 760 Torr
Pressure:
Mercury barometers
Measures atmospheric pressure by allowing the atmosphere to apply force to one end of a column of mercury
Measured pressure = F / A, where F is the atmospheric force and A is the cross sectional area of the column of mercury
Calibrated such that 1 atm = 760 mm Hg
Fluid physiology:
Alveoli
Remember that alveoli are smaller but have greater cross-sectional area compared to larger airways like the trachea.
Compared to the trachea, alveoli have lower flow velocity (think Q = vA)
Smaller alveoli have lower radii and therefore higher pressures (think Poisueille’s law) and therefore require more surfactant to keep open.
Fluid physiology:
Circulatory system
In the circulatory system, Q is analogous to cardiac output (CO)
Blood pressure = Q x R = (cardiac output) x (resistance)
Example: if there is vasoconstriction, then resistance increases, therefore blood pressure increases.
Hydrostatic principles:
Archimedes’ principle
Hydrostatic principles:
Specific gravity
Hydrostatic principles:
Hydraulic lift
