HORIZONTAL JETS IN A ROTATING STRATIFIED FLUID

A horizontal jet emerging continuously from a small round nozzle (conc entrated source of momentum) in a rotaing stratified fluid is investig ated using laboratory experiments. The jet either (i) deflects from th e direction of injection, forming an anticyclonic spiral monopole (mon opole regime), or (ii) propagates along the injection direction, formi ng a dipolar structure (dipole regime). Which of these characteristic flows occurs depends on the system parameters, the Reynolds number Re, and the buoyancy frequency to Coriolis parameter ratio N/f; a flow re gime diagram is developed for the parameter ranges 40 less than or sim ilar to Re less than or similar to 200 and 0 less than or similar to N /f less than or similar to 35, respectively. A theoretical analysis is advanced to explain the conditions under which the monopole and dipol e regimes occur, including the transition curve between the two regime s. The theory is supported by laboratory experiments. Some geophysical examples of the considered flows are discussed. (C) 1997 American Ins titute of Physics.