非线性物理：形态发生 wiin mAAAAns Flg.3.Hele-Shaw experiment in which the inviscid fluid enters through a central orifice and forms fingers that move radially outward.One of these fingers has trapped a small bubble at its tip.As a result,it is growing stably at constant speed and is emitting sidebranches.(Photograph courtesy of Y. Couder.)非线性物理：形态发生