Prediction of CO level near vehicular tunnel with waiting queue

A mathematical model is developed to predict the resultant carbon monoxide level in a residential area located near a vehicular tunnel entry. The highway to the tunnel is adjacent to hillsides. The tunnel is ejecting polluted air with a speed of 5 m/s and a carbon monoxide concentration of 200 ppm. A waiting queue of vehicles forms in front of the tunnel entry at rush hours. The effect due to the tunnel jet together with this vehicular queue is simulated under the action of wind. This mathematical model is set up from a system of recirculation flow equations using a two-equation k-ε turbulent model. The equations are solved numerically for primitive variables with three-dimensional effect. The set of partial differential equations are discretized using the control volume method and numerical scheme employed is the SIMPLER. The predicted results are useful to justify the environmental impact on the residential area located 300 m within the tunnel entry.