Receiver Sand Mitigation Measures along railways: CWE-based conceptual design and preliminary performance assessment

Abstract

Desert railways are constantly exposed to incoming wind-blown sand. The railway structure locally disturbs the incoming sand drift, induces its accumulation, and ultimately suffers its harmful effects. Receiver Sand Mitigation Measures (SMMs) aerodynamically interact with the track system, induce sand erosion around it, and allow sand transport far downwind it. The conceptual and preliminary design of an innovative Receiver SMM called Sand Blower is developed in this study. The design is grounded on the aerodynamic behaviour of the baseline humped sleeper track system. The flow control strategy is intended to avoid boundary layer separation, and to promote local flow acceleration by means of the Venturi effect. The performance assessment is carried out by Computational Wind Engineering approach. It allows to simulate the local wind flow, to obtain the shear stress field at the wall, and to derive from it sand sedimentation, windward erosion and backward erosion conditions. The results show that the Sand Blower greatly increases the track system performance by reducing sand sedimentation and increasing sand erosion under wide range of wind speeds and directions.