Aerodynamics I Posted on January 12, 2019 by aerovijay The study of the properties of moving air and the interaction between the air and solid bodies moving through it.External aerodynamics is the study of flow around solid objects of various shapes. Evaluating the lift and drag on an airplane or the shock waves that form in front of the nose of a rocket are examples of external aerodynamics. Internalaerodynamics is the study of flow through passages in solid objects. Which statement relates to Bernoulli's principle? Air travelling requires some external force Air is easily travel from low region to low region Air traveling faster over the curved upper surface of an airfoil causes lower pressure on the top surface. None of these The angle of attack at which an airplane wing stalls will Change with an increase in gross weight Remain the same regardless of gross weight Increase if CG is move forward None of these Within the mean free path of molecule, flow passes from Supersonic state Subsonic state Subsonic to supersonic state Supersonic to subsonic state Which basic flight maneuver increases the load factor on an airplane is campared to the straight and level flight? Stalls Turns Climbs Roll When flow passes from supersonic to subsonic state, Pressure increases Velocity decreases Both of the mentioned None of these Which among the following is the formula for volumetric flow rate? Q = v/A Q = Av Q = A+v Q = A-v Which among the following is the formula for mass flow rate? Q = m/p Q = mp Q = m + p Q = m – p Compressible flow is a flow that deals with ______ Fluid temperature Fluid pressure Fluid density Fluid geometry Which among the following is an assumption of the compressible flow? Resistance to flow of object Known mass flow rate Resistance to flow of heat No-slip condition What is Mach number? Speed of object * speed of sound Speed of object /speed of sound Speed of object + speed of sound Speed of object- speed of sound The boundary layer thickness is taken to be at a distance from the plate surface to a point at which the velocity is given by u = 0.33 U INFINITY u = 0.50 U INFINITY u = 0.75 U INFINITY u = 0.99 U INFINITY The conditions for flow beyond the boundart layers and its outer edge are________ d u/d y = 0 and u = U 0 d u/d y = 1 and u = U 0 d u/d y = 0 and u = U INFINITY d u/d y = Infinity and u = U INFINITY The end states of normal shock must ____ Fanno line. Lie on Lie below Lie abov None of these The Prandtl Number approximates ___________ Momentum diffusivity to thermal diffusivity Thermal diffusivity to momentum diffusivity Shear stress to thermal diffusivity Thermal diffusivity to kinematic viscosity Air foils when designed to work in water are called as _________ Dynamic air foil Hydro foil Both are correct None of these Airfoil when passed through fluids produces ________. Drag Thrust Drag & thrust None of these Relation between angle of attack and _______ for invincible fluids is found in thin airfoil theory. Lift Drag Lift & Drag None of these In subsonic flight air foil has a shape of round at the leading edge. True False Cambered air foils generate lift at ________ angle of attack. Zero High Low Moderate angle of attack In air foil lift is __________ proportional to angle of attack. Inversly Not related Directly None of these Slope between lift coefficient and angle of attack in a line is __________ 70 degree 360 degree 90 degree 180 degree The exit velocity in the nozzle increases as per __________ Stagnation point Continuity equation Prandtl Number Newton’s law Center of pressure lies exactly in ________ of the chord from the leading edge in a symmetrical air foil. One quarte Half Three fourth None of these Aerodynamic center lies exactly at ______ on the chord from leading edge in cambered air foil. Half One quarter Three fourth None of these Which aerodynamics force is known as "the resistance of air"? Thrust Weight Lift/gravity Drag In straight and level flight, unaccelerated flight, the sum of opposing forces acting on the aircraft always______. Positive Negative Zero OMG Edson Typically a wing is designed to stall from_____to_____resulting is more effective aileron control during stall. Leading edge to trailing edge Bottom to top Wing root to wing tip Wing root to center of airfoil Pressing down on the pedals turns the rudder. Moving the stick from side to side raises or lowers the ailerons. The rudder turns the aircraft, and one aileron goes up while the other goes down, banking the aircraft as it turns. Note that this animation only shows the yaw movement and not the banking. Which is called____? Turnign (Yaw) Pitch-up Pitch-down Forward What is the cockpit? Powered by the engine and providing thrust The pilot moves the stick to one side Assemble of engine compartment Control center where pilot, instrumentation, and navigational aids are located When are the four forces that act on an airplane in equilibrium? During take off During unaccelerated flight During descent of flight During airplane nose rises What is the relaitonship between of lift, drag, thrust and weight when the airplane is in straight and level flight? Lift equals to drag and thrust equals to weight drag equals to weight and lift equals to thrust Drag equals to thrust and lift equals to weight Thrust equals to lift and weight equals to drag The location of CG with respect to center of lift What must pilot be aware of as results of ground effect? What forces makes an aircraft turn? The tern "angle of attack" angle between the What determines the longitudinal stability of an airplane? Stalled : Loading an airplane to the most aft CG will cause the airplane to be : The acute angle in the angle of : In what flight condition must an aircraft be placed in order to spin? In what flight condition is torque effect the greates in an single-engine airplane The amount of excess load that can be imposed on the wing of an airplane depends upon the: Unaccelerated of airplane In order to descent of airplane Back-thrust of engine The speed of the airplane Increase the angle of descent without increasing the airspeed. Changes in the center of pressure of a wing affect the airacraft One of the main functions of flaps during approach and landing is to: Ground effect is most likely to result in which problems? Select the four fligt fundamentals involved in maneuvering of aircraft Less stable at all speed : Change in the center of pressure of a wing affect the aircraft's Loading an airplane to the most aft CG will cause the airplane to be: During the spin to the left, which wings(s) is/are stalled? During an approach to a stall, an increased load factor will cause the airplane to: If you load an aircraft tail-heavy, the center of gravity (CG) will be aft and the nose will more easily_______than if it were in forward loading configuration. Upward Downward Neutally None of these Aerodynamics_____ the science of within the atmosphere the forces of air in motion Components that are specifically designed to produce lift,thrust, or stability. the front part of an airfoil If the gauge pressure on a standard day at sea level 25 PSI, the absolute pressure is______ 22.5 PSI 39.7 PSI 45.4 PSI 32.4 PSI What is the sea level pressure? 1222.4 mb 1032.2 mb 1013.2 mb 44.2 mb Standard Sea level temperature is_______ 15 degrees Celsius 20 degrees Celsius 0 degrees Celsius 22 degrees Celsius At what altitude is the tropopause______ 11,0000 ft 12,000 ft 33,000 ft 36,000 ft What is the approximate temperature of oxygen is in the atmosphere? 23% 21% 25% 27% A pressure of one atmosphere is equal to_______ 14.7 psi 1 inch Hg 10.12 psi 12.3 psi A barometer indicates_______ Temperature Pressure Density Velocity of Air Which is the ratio of water vapour actually present in the atmosphere to the amount that would be present if the air were saturated at the prevailling temperature and pressure? Absolute humidity Dew point Relative humidity None of these What is the absolute humidity____ The amount of water vapour, usually discussed per unit volume The temperature to which humid air must be cooled at constant pressure to become saturated The amount of water vapour in the mixture of air and water vapour None of these What is not one of the four forces of flight? LIft Drag Pressure Thrust Aeronautics______ The front of an airfoil The science of within the atmosphere The flow of air which moves opposite the flight path of an airplane Motion of particles Ambient Pressure is the pressure of the Surrounding medium such as a fluid or a gas which comes into contact with the object Atmosphere at the altitude at which the aircraft is flying Result of the velocity through a fluid or gas Feeling in a restaurant or nighclub Pressure altitude is the pressure of the Difference in density with International Standard Atmosphere (ISA) temperature Physical distance between aircraft and reference (e.g. Sea Level) Differential with respect to Pressure at Sea Level Distance between Center of Earth and parallel surfaces around the spherical earth. Gravitational potential same on a surface Geometry altitude is the_____ Pressure differential with respect to Pressure at Sea Level Physical distance between aircraft and reference (e.g. Sea Level) Difference in density with International Standard Atmosphere (ISA) temperature Distance between Center of Earth and parallel surfaces around the spherical earth. Gravitational potential same on a surface Geopotential altitude is the_____ Distance between Center of Earth and parallel surfaces around the spherical earth. Gravitational potential same on a surface Difference in density with International Standard Atmosphere (ISA) temperature Measure of the specific potential energy at the given height (relative to the Earth's surface) Pressure differential with respect to Pressure at Sea Level Density altitude is the______ Pressure differential with respect to Pressure at Sea Level Physical distance between aircraft and reference (e.g. Sea Level) Difference in density with International Standard Atmosphere (ISA) temperature Distance between Center of Earth and parallel surfaces around the spherical earth. Gravitational potential same on a surface Which parameter cannot be computed if the pitot tube (dynamic pressure sensor) becomes clogged? Air speed Vertical speed Aititude None of these Indicated Air speed is_____ Airspeed measurement from difference in pressures Airspeed correcting for instrument errors Airspeed corrected for Compressibility effects Actual relative speed between aircraft and airmass, corrected for difference in density at different altitudes Shock wave is the_______ Proportional to temperature Motion around the body Propagating disturbance None of these The ISA assumes a standard day is taken from equator is taken from 45 degree latitude none of these At higher altitudes as altitude increases, pressure increases exponentially decreases at constant rate decreases exponentially increases at constant rate When the pressure rate half of that at sea level, what is the altitude? 7000 feet 13,000 feet 18,000 feet 13,000 feet