Euleruv-Lagrangeuv model simulující dynamiku dopravy a její vliv na provozní větrání tunelu

Eulerian-Lagrangian model for traffic dynamics and its impact on operational ventilation of road tunnel

conference paper

en

The contribution deals with a computational Eulerian-Lagrangian model that simulates movement of cars inside a road tunnel and its impact on operational ventilation. The model simulates moving cars as a discrete objects that "fly" through the tunnel. The objects are treated with Lagrangian momentum equation and their velocity is solved along their trajectories that are determined by the shape of the roadway. The ambient air is solved with a commercial CFD code StarCD. Due to drag force, the cars virtually change their velocity, but this latter is continuously re-set to its original value. Momentum equation for continuous phase contains an additional source term that results from the net efflux of momentum of cars when they enter and leave a particular control volume of the solution domain. The model [1] can simulate cars moving with different speed and traffic rate in individual traffic lanes. As a result we obtain flow rate generated by moving vehicles as a function of traffic speed and traffic rates. Turbulence was modelled using standard k-e model with three different formulas for extra sources of the kinetic energy of turbulence that account for additional turbulence generated by moving vehicles.. The traffic induced turbulence shows a non-negligible effect on the total flow rate inside the tunnel. The model was validated with experimental data from Chen et al. (1998), where the small-scale tunnel 1:20 was investigated. The experiments were carried out with a moving belt carrying small like-car objects. The tunnel length was 20m, the height 36.5cm and the tunnel had two parallel lanes. Several traffic densities and speeds were simulated, namely 10000, 20000 and 30000 cars/hour per lane with speed of 20km/hour and 40 km/hour.

V příspěvku je prezentován Euleruv-Lagrangeuv model simulující pohybující se automobily v dopravním tunelu a jejich vliv na větraní tunelu. Model umožňuje simulaci pohybujících se automobilů s různou rychlosti a hustotou provozu v jednotlivých jízdních pruzích. Model rovněž zahrnuje i turbulenci indukovanou pohybem automobilů.

The contribution deals with a computational Eulerian-Lagrangian model that simulates movement of cars inside a road tunnel and its impact on operational ventilation. The model simulates moving cars as a discrete objects that "fly" through the tunnel. The objects are treated with Lagrangian momentum equation and their velocity is solved along their trajectories that are determined by the shape of the roadway. The ambient air is solved with a commercial CFD code StarCD. Due to drag force, the cars virtually change their velocity, but this latter is continuously re-set to its original value. Momentum equation for continuous phase contains an additional source term that results from the net efflux of momentum of cars when they enter and leave a particular control volume of the solution domain. The model [1] can simulate cars moving with different speed and traffic rate in individual traffic lanes. As a result we obtain flow rate generated by moving vehicles as a function of traffic speed and traffic rates. Turbulence was modelled using standard k-e model with three different formulas for extra sources of the kinetic energy of turbulence that account for additional turbulence generated by moving vehicles.. The traffic induced turbulence shows a non-negligible effect on the total flow rate inside the tunnel. The model was validated with experimental data from Chen et al. (1998), where the small-scale tunnel 1:20 was investigated. The experiments were carried out with a moving belt carrying small like-car objects. The tunnel length was 20m, the height 36.5cm and the tunnel had two parallel lanes. Several traffic densities and speeds were simulated, namely 10000, 20000 and 30000 cars/hour per lane with speed of 20km/hour and 40 km/hour.

road tunnel, CFD modeling, Eulerian-Lagrangean approach, traffic induced flow and turbulence

2003

07.07.2003

Luzern

855980479

Aerodynamics & Ventilation of Vehicle Tunnels

2003

15