Investigation of squeal noise generation in wheel-rail contact under wet conditions using a twin-disc test rig

This study investigates the potential of water lubrication to reduce wheel squeal noise in tramway turnaround loops, focusing on low rolling speeds. A combination of experimental testing and simulation modelling was used to assess the effect of water on noise generation under varying rolling speeds, angles of attack and loads. Vibro-acoustic measurements identified dominant frequency modes and quantified noise levels in dry and wet conditions. The results show that water alters the noise dynamics by shifting the dominant frequency modes as a function of load and speed. Unlike dry conditions, wet SPL does not show a consistent monotonic increase with rolling speed. While water does not eliminate squeal, it reduces excitation, achieving 10-20 dB noise reduction at higher speeds but only 2 dB at lower speeds. The results support the quasi-static and instantaneous creep curve hypothesis, consistent with the studies of Liu and Meehan. This study provides evidence that water lubrication is an effective, environmentally friendly alternative to chemical friction modifiers for the reduction of squealing noise.