An improved correlation for pressure drop in a tunnel under traffic jam using CFD

作者：Eftekharian Esmaeel; Abouali Omid^*; Ahmadi Goodarz

来源：Journal of Wind Engineering and Industrial Aerodynamics, 2015, 143: 34-41.

DOI：10.1016/j.jweia.2015.04.013

• CFD
• Traffic jam
• Tunnel
• One directional
• Pressure drop

Undoubtedly, an accurate estimation of pressure drop due to vehicles can contribute to correctly predicting the number of jet fans which ultimately leads to choosing the optimum ventilation system in a tunnel. The main objective of the present study is to improve the 1D (one-dimensional) model, which currently is unable to consider the effects of combination of cars in traffic jam on the total drag force. The CFD technique has been applied to model several tunnels in different lengths under severe traffic jam conditions; this way, the difference between pressure drop predicted by CFD simulation and 1D model can be investigated. The CFD simulation results were used to develop a new correlation for pressure drop due to cars inside the tunnel as a function of tunnel average air velocity and tunnel length. Additionally, the differences between the pressure drop due to the cars predicted by the CFD and the 1D model for different traffic conditions were investigated. It was shown that the existing 1D model underestimates or overestimates the pressure drop depending on the traffic condition and the drag-area value used in analysis. Finally, 1D model is modified by a simple equation for the pressure drop in a tunnel in congested traffic conditions using an equivalent friction factor resembling the stopped vehicles.

• 出版日期2015-8