人類一直以來都想要探索生物科技的奧秘。隨著生物科技的進步與發展，人們因此想要了解機械式的刺激（mechanical stimulation）與生物體之間的關聯性。雖然活體（in vivo）實驗是生物科技最後的必經之途，但由於進行活體試驗有程度上的困難以及考慮人道問題，因此詳實的體外（in vitro）試驗便成為現今生醫工程研究所仰賴的方法，是一重要且不可忽略的生物醫學步驟。 生物反應器(bioreactor)可以提供一個體外的細胞培養生長反應的環境，進行細胞的培養和增長。在各種生物反應器中，以圓錐平板型粘度計（cone-plate viscometer）為架構的生物反應器廣為學者使用，由於此反應器可以模擬血液流動對內皮細胞所造成的流體剪應力(Fluid Shear Stress)，研究剪切力對血管內皮細胞的生長影響。 本篇以圓錐平板型生物反應器為基礎，利用擾動法（perturbation）對於速度及壓力進行雙重展開（double expansion），建構在圓錐平板型生物反應器中的流動情形，分析週期（periodic）變化對二次流動（secondary flow）及流體剪切力分佈的影響，以期研究結果應用於生物科技之中。 With the development of biomechanics, people want to know how mechanical stimulations relate to a living thing. Although experiments in vivo are the ultimate way in biomechanics, considering about the difficulties and human sympathy, it is now very important and indispensable to depend on processing experiments in vitro for biomechanics. Bioreactor is an apparatus, which provides an environment for cultivating cells in vitro. For broadly approach to cell mechanostimulus by fluid shear stress, cone-plate instrument has been used as a bioreactor, in which rotation is imposed about a cone axis oriented perpendicular to the surface of a flat plate. Using the cone-plate instrument as the bioreactor, we analyze the periodic flow by periodically rotating the cone on the plate. The flow field induced by the rotating cone has investigated analytically by expanding the Navier-Stokes equations and the continuity equation with two nondimensional parameters, the first Reynolds number and the square of the Womersley parameter . We found that secondary flow and the shear stress on the plate are seriously influenced by the periodic motion of the cone.
