Assessment of aerodynamic performance

Mathematical modelling of the aerodynamic characteristics of the EMU design taking into account required operating speeds and wind loads. Modelling results are accounted for in traction characteristic calculations to achieve the specified acceleration parameters.

• Development of mathematical models of the designed high-speed rolling stock using a computational software suite followed by numerical modelling of oncoming flow aerodynamic effects and wind loads corresponding to the climatic zone of operation. Assessment of airflow generated by rolling stock movement on open track is calculated at speeds above 200 km/h.
• Additionally, the effect of airflow on rolling stock when passing open track sections is considered.
• Results obtained from numerical studies in the software product are taken into account when designing various rolling stock components, for example the train nose fairing, roof fairings, and air-conditioning systems. Modelling results are accounted for in traction characteristic calculations to achieve the specified acceleration parameters.

Parameters evaluated by finite-volume mathematical modelling:

Overall drag resistance to forward motion Rolling stock travelling at speeds above 200 km/h experiences resistance from the air medium. This involves modelling in computational programs the complex interaction between rolling stock and the air medium

Aerodynamic effect of airflow on people on platforms or near railway tracks. The generated airflow affects people on platforms and staff near railway tracks.

Head pressure wave. When two EMUs pass each other in opposite directions, a shock air wave is generated, creating additional pressure on the rolling stock.

High-speed rolling stock passing through tunnels. When passing through tunnels, an additional airflow is formed that acts on the head end of the rolling stock.

Crosswind effect. The effect of crosswind when a train passes an open straight track section at maximum speed is assessed to ensure safe operation.

During analysis, a mathematical model of the entire rolling stock is developed for CFD analysis.

Solid models of rolling stock cars for mathematical modelling are developed using CAD software suites:

• NX;
• SolidWorks;
• Creo.

CFD software suites are used to model and calculate aerodynamic load effects on rolling stock and objects located near it:

• Ansys CFX;
• FlowVision;
• Fluent.