The discussion centers on the phenomenon of mass entrainment in jets, specifically in the context of fuel jets within diesel engines. It is established that free jets, which emerge from an orifice at high velocities, entrain surrounding air due to the conservation of mass principle. As the jet accelerates the nearby air to match its velocity, this process continues to propagate, resulting in the entrainment of additional air. The interaction between the jet and surrounding fluid is governed by principles of continuum mechanics, emphasizing the energy and momentum transfer involved.
PREREQUISITESEngineers, fluid dynamicists, and researchers interested in the behavior of jets in various applications, particularly in combustion systems and aerodynamics.
larsa said:Why the interface between the jet and the surrounding air needs to be at the same velocity?
Thank you for your answerMarkJW said:Fluids are treated as continuum mechanics. The jet has to displace air in its path, right? So it is going to transfer some energy/momentum.