Advanced Computational Aerodynamics Mid - I, September - 2014

1.In view of irrrotationality assumptions, a velocity potential exist, consequently the continuity equation reduces to
  • Reynolds equation
  • Navies – stokes equation
  • Laplace equation
  • Bernoulli’s equation
Answer: C
2.An implicit approach one where unknowns are obtained by simultaneous difference equations applied at
  • One grid point
  • specific point
  • all grid points
  • boundary
Answer: C
3.The finite-difference calculation themselves can be carried out using by_________
  • vans leer flux
  • Mac-Cormack’s method
  • Crank-Nicholas’s
  • Navier-stokes
Answer: B
4.Crank-Nicolson difference is used to solve problems governed by
  • parabolic equations
  • hyperbolic
  • elliptic
  • none
Answer: A
5.Rectangular grids allow higher order accuracy than ______________
  • parabolic
  • Poission’s equations
  • hyperbolic
  • curvilinear grid
Answer: D
6.The flow variables at these three grid points are consider known as
  • Mac-Cormack’s technique
  • Lax-Wendroff method
  • Lax- Fredrichs method
  • ADI
Answer: A
7.Vortex panel method is used for ______over arbitrary bodies
  • Lifting flows
  • non-lifting flows
  • Both lifting and non-lifting flows
  • neither lifting nor non-lifting flows
Answer: A
8.The indeterminate derivatives of flow variables are along the
  • Zero
  • characteristic lines
  • infinity
  • unity
Answer: B
9.The predictor step of explicit MacCormack algorithm uses ________for the y-derivative
  • Backward difference
  • Central Difference
  • Upward-scheme
  • Forward difference
Answer: D
10.At a given point on the surface of an airfoil ,the pressure coefficient is 0.3 at very low speed, if the free stream Mach number is 0.6.calculate Cp at this point______________
  • -0.23
  • 0.132
  • 0.375
  • -0.375
Answer: C
11.Vortex panel method is used for ______________over arbitrary bodies.
Answer: Lifting flows
12.The area between two upstream characteristics is called_______________________
Answer: Domain of dependence
13.The minimum-length supersonic nozzles are used in_______________________
Answer: Rocket Nozzles
14.A statement in transonic flow relating to drag rise that the cross sectional area distribution of the body sould have a smooth variation with longitudinal distance along the body___________
Answer: Area Rule
15.A _________________ splitting which imposes certain condition of F+ & F- to improve the performance of numerical Scheme for local Mach number.
Answer: VAN LEER’S FLUX
16.The governing equation for irrotationl incompressible flow equation is____________
Answer: Laplace Equation
17.TVD abbreviation is __________________________________
Answer: Total-Variation Diminishing
18.The region in the expansion zone of a supersonic nozzle covered by waves of only one family of characteristic lines and the other family getting cancelled at the wall is known as _____________________
Answer: Simple region
19.The Numerical methods for the Euler equations uses flux-vector splitting based________
Answer: Steger -Warming method
20.The time rate of change circulation around a curve consisting of the same fluid is____________
Answer: Zero