Aerodynamic noise from the bogie section of a high-speed train is one of the main noise sources. This paper describes methods for evaluating the noise level from the bogie section in a wind tunnel in which the flow velocity profiles at the central inlet position of the bogie section were modeled precisely. A new method for the flow modeling was designed to avoid a decreasing in the signal to noise ratio. Each flow velocity was modeled precisely by this simple method. On the basis of the two-dimensional sound pressure distribution obtained by a microphone array, the noise level at the side of the train car model was estimated. First, we found that the contribution of the bogie model itself and the side covers to the noise level is different between the leading car and the middle car. Flow velocity measurements inside the bogie cavity in the leading car also suggested that flow velocity at the rear wheel is lower than that in front of the front wheel, whereas there is little difference along the center line, which indicates a flow separation near the front bogie components. Second, we found that the difference in the noise level from the bogie section between the leading car and the middle car is smaller than the estimate calculated on the basis of the assumption that the noise level increases in proportion to the sixth power of flow velocity at the central inlet of the bogie section.
展开▼
