discritize compatability relation (Charactersitic)
 

Hello

I want to discritize compatability relation (Chaacteristic method) and use it for charactersitic boundary condtion.I have problem to discritize it please guide and help me to how to discritize this equation.or inform me with a paper or book which i can find this problem on it. i know Steger,Pulliam 1980 have got paper about it (with implicit method) but i couldnt get it.

yours Saeid