text: Recall that one of the principal effects of 
  th,e normal shock wave is to produce a large 
  increase in the static pressure of the airstream 
  is 
  If 
  the wave. 
  behind 
  the boundary layer may not have 
  strong, 
  sufficient kinetic energy to withstand 
  the 
  large, adverse pressure gradient and separation 
  will occur. At speeds only slightly beyond 
  critical Mach number the shock wave formed 
  is not strong enough to cause spearation or 
  any noticeable change in 
  the aerodynamic 
  force coefficients. However, an increase in 
  speed above critical Mach number sufhcient 
  to form a strong shock wave can cause sepa- 
  the boundary layer and produce 
  ration of 
  force 
  sudden changes in 
  coefficients. Such a flow condition is shown 
  in figure 3.9 by the flow pattern for M=O.n. 
  Notice that a further increase in Mach number 
  to 0.82 can enlarge the supersonic area on the 
  upper surface and form an additional area of 
  supersonic flow and normal shock wave on the 
  lower surface. 
  
  the shock wave 
  
  PHENOMENA OF TRANSONIC FLIGHT. 
  Associated with 
  rise” are buffet, 
  the “drag 
  trim and stability changes, and a decrease 
  in control surface effectiveness. Conventional 
  rudder, and elevator surfaces sub 
  aileron, 
  jetted 
  frequency buffet may 
  “buzz,” 
  and changes in hinge moments may 
  produce undesirable control forces. Of course, 
  if 
  the buffet is quite severe and prolonged, 
  structural damage may occur if this operation 
  is in violation of operating limitations. When 
  airflow separation occurs on the wing due to 