INTRODUCTION TO AERODYNAMICS
INTRODUCTION TO AERODYNAMICS MECH 594
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This 4 page Class Notes was uploaded by Shaina Lowe Jr. on Monday October 19, 2015. The Class Notes belongs to MECH 594 at Rice University taught by Andrew Meade in Fall. Since its upload, it has received 86 views. For similar materials see /class/224971/mech-594-rice-university in Mechanical Engineering at Rice University.
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Date Created: 10/19/15
Mmdynamlcs Terms andDe mumis 1m imp me awa nn nyemntetsiassmemwss ntm Aerodynamics Terms and De nitions veuaieheie HeinegtAv iniegtAv GiDSSaYiESgtAEVDdynamiESTEYmSandDE m iuns Aerodynamic Center ccietticient dues netvaiv With an angie cit attack change Airfoil attack are prirnariiv respunsibie ter the iitt and pretiie drag citthe Wing Angle ofAttack The angie cit attack is getiheg as the angie between th chcirg and the girecticin cit rnciticih tre varied tci increase cir ge resuits in an increase in e piane at the Wing airtciii e strearn veicicitv The angie cit attack can be crease the iitt acting en the Whg An increase in iitt citteh drag enter ofPressure A puint aicing the airtciii abuut Which the rncirnent duEtD the iitt is ZErEI ie i it is the puint cit acticin at the iitt The center at pressure Wiii change its pesiticin When the angie cit attack changes Chord Circu iation circuiaticin is a measure at the verticitv in the tieW tieig Fur an inviscig fiquiEid the iitt is eguai tci the pruduct at the EirEuiatiDn abuut the airf ii the density and the veiucity Computational Fluid Dynamics CFD Cumputatiunai uid gvnarnics is the term given tci a variety cit numericai aercigvharnics The rnass et a substa ce centaiheg in a given vuiume divided by the vuiume Fura incumpressibie uid the density is Eunsidered tci be censtaht thrciughciut the tieW fieid Huvvever ter a umpressibie uid the gehsitv can vary trern cine icicaticin tci mm 1 m m Aerodynamics Terms and Definitions httpWWWaviationbgEnInfoGlossAerodyniglosshtm the next in the flow field The speed of sound in a fluid depends on the ratio of pressure changes to density changes in the fluid Drag Drag is an aerodynamic force opposing the direction of motion Drag can be due to surface viscosity friction drag pressure differences due to the shape of an object form drag lift acting on an finite wing induced drag and other energy loss mechanisms in the flow such as wave drag due to shock waves and inefficiencies in engines Drag Coef cient The drag coefficient is defined as the dragdynamic pressure reference area The reference area is usually the planform or flat projection the wing39s shadow at noon area of the wing Dynamic Pressure The dynamic pressure is defied as the product of the density and the square of the velocity divided by two The dynamic pressure has units of pressure ie ForceArea The dynamic pressure is used to nondimensionalize forces and pressures in aerodynamics Flap Deflection Angle The flap deflection angle is the angle between the deflected flap and the chord line The angle is positive for a downwards deflection of the flap Deflect the flap downwards to increase the airfoil39s lift Lift The lift is a force acting perpendicular to the direction of flight The lift is equal to the fluid density multiplied by the circulation about the airfoil and the free stream velocity ln level flight the lift developed by an airplane39s must be equal to the weight of the entire airplane Lift Coef cient The lift coefficient is defined as the liftdynamic pressure reference area The reference area is usually the planform area of a wing or horizontal projection of the wing Mean aerodynamic chord This chord is located along the wing and has the aerodynamic property of the twodimensional wing NACA Airfoils NACA airfoils are wing cross section designs invented by the NACA organization 2 of 4 121203 107 PM Aerodynamics Terms and Definitions httpWWWaviationbgEnInfoGlossAerodyniglosshtm NACA eventually became NASA National Aeronautics and Space Administration Here are a few popular airplanes that have NACA airfoil wings Airplane Root Airfoil Tip Airfoil Beech 50 Twin Bonanza NACA 230141 NACA 23012 B17 Flying Fortress NACA 0012 NACA 0010 Cessna 152 NACA 2412 NACA 0012 Cessna 172 1973Iater NACA 2412 NACA 2412 mod Cessna 550 Citation M NACA 23014 NACA 23012 Douglas DC3 NACA 2215 NACA 2206 Fairchild A10 Thunderbolt NACA 6716 NACA 6713 Sikorsky S61 SH3 Sea King NACA 0012 NACA 0012 Panel Method This numerical method places singularities along the airfoil In the case of VisualFoil the singularities are vortices The vorticity is distributed linearly along the panel Plain Flap A plain flap is a hinge attachment near the trailing edge of an airfoil The length of the flap is measured as a percentage of the chord and the deflection is measured in degrees Pressure Coef cient The pressure coefficient is a nondimensional form of the pressure It is defined as the difference of the free stream and local static pressures all divided by the dynamic pressure Stall At low angles of attack the lift developed by an airfoil or wing will increase with an increase in angle of attack However there is a maximum angle of attack after which the lift will decrease instead of increase with increasing angle of attack This is know as stall Knowing the stall angle of attack is extremely important for predicting the minimum landing and takeoff speeds of an airplane Streamlines Contours in the flow field that are tangent to the velocity vector 3 of 4 121203 107 PM Aerodynamics Terms and Definitions httpWWWaviationbgEnInfoGlossAerodyniglosshtm Wing Loading The total weight of the airplane divided by the planform area of the wing Wing Span The span is the total length of the wing 4 of 4 121203 107 PM