Calculation of the Shear Stress in the Parallel - Plate Flow Chamber under Pulsatile Flow Condition

The parallel - plate flow chamber (PPFC) with rectangular shape, of which the height is far smaller than its own length and width, is one of the main apparatus for in vitro studies of the mechanical behavior of cultured endothe-lial cells undergoing shear stress. The PPFCs are usually utilized to study the cells' mechanical behavior under steady flow condition. The analysis of the pulsatile flow in PPFC is presented in detail in this study, and the precise formulas are derived to calculate the shear stress at the bottom of the chamber under general pulsatile flow conditions. For the pulsatile flow with small Womersley number, a quasi - steady flow expression for the calculation of the shear stress distribution is also presented. The calculated numerical results demonstrate that, the quasi - steady formula is highly precise for various commonly used flow parameters and geometrical dimensions of the PPFC, which provides theoretical basis for the calculation of the shear stress in the PPFC under pulsatile flow condition.