AS-5011 Compressible Fluid Flow
Lecture-2
Atomic views
Inviscid and viscous regions
Internal and External flows
Internal-External flow
Compressible and Incompressible flows
𝑣
𝑠𝑝𝑒𝑒𝑑 𝑜𝑓 𝑓𝑙𝑜𝑤
•𝑀= =
𝑐
𝑠𝑝𝑒𝑒𝑑 𝑜𝑓 𝑠𝑜𝑢𝑛𝑑
• Gas flows can often be approximated as incompressible if the density
changes are under about 5 percent
• The flow of a gas is not necessarily a compressible flow
Laminar, transitional, and turbulent
Steady or unsteady
Oscillating wake of a blunt-based
airfoil at Mach number 0.6
Kinematics
• Study of fluid motion without referring to the forces or moments
involved.
Eulerian or Lagrangian
Streamlines, pathlines, streaklines
Streamlines, pathlines, streaklines
Streamlines
Pathlines
Streaklines
Timelines
t4
t3
t2
t1