# Shared Flashcard Set

## Details

Intro to flight, John Anderson
Chapter 4
28
Engineering
09/25/2006

Term
 (P0/P1) =
Definition
 (1+ [(γ-1)/2]M1^2)^[γ/(γ-1)]For Isentropic Flowγ = Gamma
Term
 (Roh0/Roh1) =
Definition
 (1+ [(γ-1)/2]M1^2)^[γ/(γ-1)]For Isentropic Flow
Term
 Density1*Area1*Velocity1 =
Definition
 Density2*Area2*Velocity2
Term
 Define Isentropic Flow
Definition
 Isentropic flow is flow that is Adiabatic and reversible, meaning that:1) No heat is added or taken away2) No friction or other dissipative effects occur.
Term
 For Isentropic Flow:P2/P1 = ? = ??
Definition
 = (Roh2/Roh1)^γ = (T2/T1)^(γ/(γ-1))
Term
 Air can be assumed to be Incompressible if
Definition
 V < 100 M/s orV < 225 Miles/Houror If Mach # < 0.3
Term
 Define Eulers Equation, and explain how it is used.
Definition
 dP = -Roh*V*dVIt relates the change of momentum to the force, It is also referred to as the Momentum Equation
Term
 Define Bernoulli's Equation, and explain how it is used
Definition
 P1+Roh*[(V1^2)/2] = P2+Roh*[(V2^2)/2]OrP+Roh*[(V^2)/2] =Constant along StreamlineOnly Holds true for Inviscid(frictionless), Incompressible flow. Must NOT be used for comressible Flow
Term
 Define the Equation of State
Definition
 P1 = Roh1*(R)*(T1)R = Constant = 287 for SI, or 1716 for US.T = Temperature = Kelvin or Rankine0F = 460 Rankine0C = 273K = 32F
Term
 Define the first law of Thermodynamics
Definition
 δQ + δw = deThe sum of the heat added + the sum of the work done on the system = the change in internal energy.
Term
 Define the terms of this equationh1 + (V1^2)/2 = h2 + (V2^2)/2orh + (V^2)/2 = Constant
Definition
 h = CpT where Cp [u]=[/u] (δQ/dT) Constant Volume, T = TemperatureV = velocityAlso can be written asCpT1 + (V1^2)/2 = CpT2 + (V2^2)/2
Term
 Finish these Equations, and name them:a) Roh1*A1*V1 = b) P1 + (1/2)*Roh*(V1^2) = c) CpT1 + (V1^2)/2 =d) P1 =
Definition
 a) Roh2*A2*V2 (Continuity)b) P2 + (1/2)*Roh*(V2^2) (Bernoulli)c) CpT2 + (V2^2)/2 (Energy) (Cp =[u]=[/u] (δQ/dT) Constant Volume, T = Temperature)d)Roh1*R*T1 (Equation of state, R = 287 or 1716)
Term
 The speed of sound in a perfect gas depends only on ...
Definition
 ...The temperature of the gas.a = Sqrt(γRT) = Speed of soundγ = 1.4 for Air on earth
Term
 Define mach number:M =
Definition
 V/a, where V is the speed of the object (in ft/s) and a is the speed of sound (in ft/s)a must be determined by the equation: a = Sqrt(γRT) = Speed of soundγ = 1.4 for Air on earthif Altitude is given, use altitude table to determine TIf M<1, flow is subsonicif M=1, flow is sonicIf M > 1, flow is supersonicif M >> 1, flow is hypersonic ( M > 5)If 0.8 [u]<[/u] M [u]<[/m] 1.2, flow is transonic
Term
 Convert 550 Mi/h to ft/s:
Definition
 88 ft/s = 60 mi/h ...Therefore 550 (Mi/h)*(88/60) = 807 ft/s
Term
 For a manometer used to measure pressure differences in a wind tunnel:P1*A = orP1-P2 =
Definition
 = P2*A + ω*A*Δhor= ω*A*Δh ω*A*Δh = [Roh(fluid)*g(gravity)]*(Area)*(difference of heights between two tubes)
Term
 When dealing with low speed subsonic flow:
Definition
 V2 = Sqrt[(2*(P1-P2))/(Roh*(1-(A2/A1)^2))]since we asume Roh1 = Roh for low speed subsonic flow.
Term
 When calculating Mass flow:M =
Definition
 Roh1*A1*V1orRoh*A1*V1 for low speed subsonic airflowalso = Roh*A2*V2.Can be measured anywhere in the airflowM = roh*A*V
Term
 Compare static and total pressure
Definition
 Static pressure is the pressure felt by a particle of air in the airflow, while Total presure is the presure felt by a foreign object in the airflow.For ex, A bug flies into you inside your car while you are driving, windows up, at 60mph. since both you and the bug are doing 60mph, the force is very small. now if you open the window, and the bug flies out and hits a person standing on the side of the road, the force is much greater, since the bug and person are not traveling the same speed.
Term
 Define Vtrue and VeVtrue = Ve =
Definition
 Sqrt[(2*(P0-P))/Roh] for VtrueSqrt[(2*(P0-P))/Roh(s)] for Ve, where Roh(s) is the air density at sea level
Term
 A pitot tube is used to measure air pressure acting on an aircraft. The equation for this is P0/P1 =P0 = total pressue,
Definition
 (1 + [(γ-1)/2]*M1^2)^[γ/(γ-1)] γ = 1.4
Term
 The relationship between T0 (total temperature) and T1 (static temperature) is given byT0/T1 =
Definition
 1+ [(γ-1)/2]*M1^2 γ = 1.4
Term
 The relationship between Roh0 and Roh1 is shown by the equation :Roh0/Roh1 = Roh0 = Total densityRoh1 = static Density
Definition
 = (1 + [(γ-1)/2]*M1^2)^[1/(γ-1)] γ = 1.4
Term
 As a fluid element flows through a shock wavea) Mach number (M)b) static pressure (P1)c) static Temperature (T1)d) flow velocitye) Total Pressure (P0)f) Total temperature (T0)
Definition
 a) decreasesb) increasesc) increasesd) decreasese) decreasesf) stays the same (for a perfect gas)
Term
 For Pitot Tubes in supersonic airspeeds, the shockwave must be accounted forP(02)/P1 =
Definition
 {[((γ+1)^2)*M1^2]/[4*γ*M1^2-2(γ-1)]}^[γ/(γ-1)] All that ^^ Times (*) [1-γ+2γ*M1^2]/(γ+1)Rayleigh Pitot Tube formula, where P(02) is the total P behind the wave, and P1 is the tatic pressure infront of the wave.
Term
 a) For subsonic airflow, for the velocity to inrease, the Area must ...b) for Supersonic airflow, for the velocity to increase, the area must
Definition
 a) decrease ( think subsonic wind tunnel)b) Increase (think rocket engine nozzle)
Term
 The boundary layer that surrounds an object in an airstream is caused by
Definition
 friction between the gas and the surface of the object
Term
 The shear stress due to air resistance is
Definition
 τw = μ*(dV/dY), Y = 0μ = absolute viscosity coefficient of the gas (mass/(length*time))
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