Question-and-answer based CAPATCHA activated
 

We have had problems recently with bots that automatically register thousands of spam users. Clearly our text-based CAPATCHA system, where a new user has to enter a few distorted characters from an image, has been broken. I have instead today activated a questions-and-answers based CAPATCHA system using a bunch of CFD-related questions that most CFD engineers should have no problems with.

If you have problems to answer one of these CAPATCHA questions please let me know. We should have questions that are difficult to answer for spammers, but easy to answer for anyone interested in CFD.