後方よどみ点非定常境界層に関する精密理論解析的研究

抄録

The fundamental problem of the impulsively started, unsteady boundary layer at a rear stagnation point has been analyzed theoretically. Our previously published, original phenomenological viscous diffusion theory and the numerical analysis with a rational nondimensionalizing scaling technique based on the said phenomenological theory are further expanded, and a new numerical method of double-layer matching is developed for the present flow of a double-layered structure. This method can give highly accurate solutions over an extremely long nondimensional time T of up to 16, while Dommelen-Shen [JFM, 157 (1985), 1-16]'s Lagrangean numerical method, which is so far considered to be the best method for the present problem, cannot give a solution beyond T=7. Furthermore, it has been proven mathematically that Proudman-Johnson [JFM, 12 (1962), 161-168]'s and Robins-Howarth [JFM, 56 (1972), 161-171]'s asymptotic solution exists, to be sure, but does isolated only at T=Q, and the correct solution starting from T=0 does not approach their solution as T→∞.