text: The previous flow across a wedge in a 
  supersonic airstream would allow flow in ;UU 
  dimensions. 
  If a cone were placed in a super- 
  sonic airstream the airflow would occur in 
  three dimensions and there would be some 
  noticeable differences in flow characteristics. 
  Three-dimensional flow 
  the same Mach 
  number and flow direction change would pro- 
  less change in 
  duce a weaker shock wave with 
  pressure and density. Also, this conical wave 
  formation allows changes in airflow that con- 
  tinue to occur past the wave front and the 
  wave strength varies with distance away from 
  the surface. Figure 3.5 depicts the typical 
  three-dimensional flow past a cone. 
  
  for 
  
  Oblique shock waves can be reflected like 
  any pressure wave and this effect is shown in 
  figure 3.5. This reflection appears logical and 
  necessary since the original wave changes the 
  flow direction toward the wall and the reflected 
  wave creates the subsequent flow change to 
  cause the flow to remain parallel to the wall 
  surface. This reflection phenomenon places 
  definite restrictions on the size of a model in a 
  wind tunnel since a wave reflected back to the 
  model would cause a pressure distribution not 
  typical of free flight. 