248 
See. 18 a 
Fig. 18-1 
In this case, if the piston is later brought to rest, a rarefaction 
wave is started which should behave the same way as the rarefaction wave 
in the corresponding shock wave case, i.e. according to Fig. 18-2, except 
that it does not catch up with the detonation wave since here D= c+ Ww. 
fi / Rare- i 
faction U=0 Fig. 18-2 
x / / wave ie ‘s 
a Piston 
pe 
¥ ' 
If the time during which the piston is being slowed down is decreased, 
in the limit a situation such as shown in Fig. 13-3 should prevail. 
‘ 
/ / raret sn 
Fig. 10-3 
Now suppose the length of time the piston travels to be reduced to a 
minimum. In the limit, the situation would look like Fig. 13-4. 
/ iy 
rare- 
gas faction fo 
at / wave ae 
Fig. 18-4 
