Front Shape and Slipstream for Wide Body Trains at Higher Speeds

Astrid Herbst, Tomas Muld, Gunilla Efraimsson (Bombardier)

CHALLENGE - Study the slipstream air speeds of wide body Bombardier trains at high speeds so that designers can meet the various requirements for front end shapes and develop a prediction methodology.

SOLUTION - Calculations on train geometries with different head and tail shapes were performed and compared to the experimental data. Before setting up the multi-objective optimization the different objectives were investigated and optimized separately both to estimate the potential and to check possible correlations. A solid understanding of how such train length affect wake structures and thus the slipstream and with it the train's energy consumption was developed. Numerical results were supplemented with water / wind tunnel tests for verification. Shape optimization of the front was carried out and resulting front shape was tested in the wind tunnel. 

BENEFITS - An efficient optimization methodology implemented in modeFRONTIER helped optimize the performance and take all constraints into account early in the design cycle saving time and cost. Derivation of a shape optimized front with respect to the slipstream, drag and pressure distribution around the nose to a wide trains that meets the requirements of the TSI to 250 kph. The fact that the final head design is optimized for drag also improves the slipstream performance.