Numerical Study of Aerodynamics of Road Tunnels

• Main Authors: Hwang, Wen-Liang, 黃文亮
• Other Authors: Liang Shen-Min
• Format: Others
• Language: zh-TW
• Published: 1996
• Online Access: http://ndltd.ncl.edu.tw/handle/09288515012213499249

碩士 === 國立成功大學 === 航空太空工程學系 === 84 === In a road tunnel, there are a lot of problems to be solved. these include thedilution of high concentration of pollution, lowering high air temperature andsmoke expelling in case of fire inside the tunnel with the operation of a ven-tilation system. To determine the power of fans used for ventilation,we have to estimatethe energy losses caused by cars and to understand the detailed flow structureinside the tunnel.In this study,the flow phenomenon when air flowed over carsis numerically simulated.The parameters which characterize the flow are: (1) the Reynolds number, (2) the distance between two cars, (3) the height of a car, (4) the ventilated flow quantity. The finite volume method is employed to solve the incompressible two dimen-sional Navier-Stokes equations. The algorithm used is based on the method ofartificial compressibility and the higher-order upwind MUSCL technique for theconvective terms and the second-order finite-differences for the viscous termsA second-order, two-step, Runge-Kutta integration coupling with an implicitresidual smoothing technique is used for achieving fast convergence for theunsteady flow problem. The total pressure losses and flow characteristicscaused by the moving cars at different unventilated or ventilated conditionsare determined by varying the values of flow parameter defined above.