一黏性流體夾於兩平板間，一板固定，另一板承受週期運動。因爲原流爲非定常狀況，其間之流體不可能維持層流。本文以微擾法(Perturbation method)探討板面過期頻率ω與流體雷諾數R對安定性之影響。以數學推演結果，發現頻率與雷諾數對安定有互助長或相抵消交連作用，但在每個定值頻率下，確有其特定臨界雷諾數，此臨界雷諾數隨著頻率增加而降低；當頻率低於ω=1•0之後，臨界雷諾數急劇高升，此一趨勢正符合『定常柯第(Steady Couette Flow)流必爲安定』之結論。
A viscous liguid is confined between two plates, one fixed and other subject to a period oscillation. Since the primary flow is not steady, the flow no more keeps in the laminar state. By the perturbation method, this report discussed how the oscillation frequency and the Reynolds No. relate to the stability of periodic Coutte flow. This mathematically analytic results point out the mutual interaction of frequency and Reynolds No. to the flow stability, enhancing or decaying; but for each specified frequency, there exactly exists a definite critical Reynolds No., and this critical No. lowers as the input frequency increases then, after the frequency drops to no more than ω=1.0, the critical No. drastically rises up, and this tendency exactly fits the closure ”steady Coutte flow is surely stable”.
