General Brazilian
liberar a raiva / desabafar a raiva
Most common usage in Brazil
Rio de Janeiro
descarregar a raiva
Common colloquial expression in Rio
São Paulo
liberar a raiva / botar para fora a raiva
Standard usage with occasional colloquial variants
Portugal
libertar a raiva / desabafar a ira
Portuguese European variant; 'ira' is more formal than 'raiva'