An under-expanded hydrogen jet from high-pressure equipment or storage tank is a potential incident scenario. Experiments demonstrated that the delayed ignition of a highly turbulent under-expanded hydrogen jet generates a blast wave able to harm people and damage property. There is a need for engineering tools to predict the pressure effects during such incidents to define hazard distances. The similitude analysis is applied to build a correlation using available experimental data.

The broad use of hydrogen as an energy carrier to tackle the issue of climate change is unavoidable. The emerging hydrogen economy poses new problems to be solved to ensure a level of safety in hydrogen technologies and infrastructure comparable to that for today’s fossil fuels. The pressure of onboard hydrogen storage in early-market