Urban Cable transportation. Comfort, performances and security in turbulent environment – TURB-Cab

The project tackles the matter of comfort and performances of Cable Transport (CT) systems in urban areas. Many recent transportation projects exploit these systems with two main advantages (i) an implementation/operation cost to carrying capacity ratio among the smallest of transportation systems, and (ii) minimized carbon footprint and nuisances. A cable car cabin carrying passengers is a moving mechanical system hanging from a cable with several degrees-of-freedom (pendular movement) and subjected to surrounding wind loads. The development of CT in urban areas comes with new constraints. These urban areas are indeed specifically characterized by winds with high turbulence intensities and masking effects from neighbouring constructions or topography which may result in strong wind gusts. The aerodynamical couplings between the cabin and the surrounding flows may result in strong oscillations and instabilities, both source of discomfort and of potential safety issues. Our project aims at unveiling the fundamental mechanisms driving these effects (via laboratory experiments and simulations), in order to propose accurate predicting models and operational strategies relevant for industrial partners to design future cabins meeting comfort and safety requirements.
The first aim of the project is therefore to gain detailed fundamental knowledge on fluid-structure interaction (FSI) phenomena occurring between a pendular system and a surrounding turbulent (“urban-like”) wind. This knowledge comes through the identification of the role played (i) by the geometrical complexity of the cabin (aspect ratio, sharp vs smooth edges, etc.) and (ii) by oncoming wind conditions (turbulence intensity, turbulent scales, temporal and spatial variabilities, etc.) on the pendular dynamics and on the mechanisms triggering instabilities. The scientific exploration of this field is very open because very few works have been dedicated to FSI for blunt swinging bodies and, at the scales considered, non-equilibrium aerodynamics at large Reynolds numbers. Progress is expected in understanding through the implementation of detailed experiments, the development of intensive numerical simulation and reduced-order modelling. In addition, the work proposed brings concrete improvements in terms of performance and comfort of the lines.
Based on the knowledge gained during the project, the second aim is to develop a general methodology, useable at an industrial level, to quantify the stability of cable transport cabins according to their characteristics and those of the nearby urban environment in which they operate. This methodology will combine experimental approaches, high-fidelity computations, and reduced-order/physical modelling of the problem to provide a robust reduced-scale approach. Finally, the third aim is to provide relevant proof of concepts studies for aerodynamic control of these oscillations implying passive or active approaches.
The project will take place on a period of 48 months. The research work will be structured around five technical tasks with strong interaction among them. A key factor for the success of TURB-Cab is the combination of the respective skills of the partners in a highly complementary research work. Industrial partners, the STRMTG and CSTB have a deep knowledge of the mechanical properties of the cable ropeways and of the environmental issues in urban environments. Academic partners are experts in the fields of fundamental fluid mechanics, aerodynamics at high Reynolds numbers and turbulence using wind tunnel experiments, high fidelity computational fluid mechanics or reduced order modelling.