Give it some noise and it starts working (or wait a few seconds and it starts working by itself).
This circuit generates a triangular wave at his output. This is a generator there is no input.
If you change the values of the resistors the frequency changes.
The output wave has a period of:
T = 2RC * ( (Vs1 - Vs2) / Voh)
R is the value of the upper resistor
C is the value of the capacitor
Vs1 and Vs2 are the threshold voltages (in this case 4.71V and -4.56V)
Voh is the maximum output voltage of the op amp (in this case 15V)
