Interaction between dry granular flow and rigid barrier with basal clearance: analytical and physical modelling

TLDR

Barriers with a basal clearance allow small discharges to pass, reducing maintenance, while also affecting impact force, jump height, and discharge. The study experimentally investigates dry granular flow interaction with a rigid barrier having basal clearance and introduces a new impact model. Experiments varied the clearance‑to‑particle diameter ratio from 0 to 10 and channel inclination from 15° to 35° to achieve different Froude numbers, enabling evaluation of the proposed impact model. Results show that a clearance of at least three particle diameters reduces impact force and overflow, underscoring the need to account for basal clearance in multi‑barrier design.

Abstract

Some types of barriers are designed with a clearance between the bottom of the barrier and the channel bed. This feature allows small discharges to pass, thereby reducing the maintenance required over the service life of the barrier. Aside from the practical function of a clearance, it influences the impact force, jump height, and discharge. In this paper, a series of physical experiments was conducted using a 6 m long flume to model the interaction between dry granular flow and rigid barrier with a basal clearance. The ratio between the clearance and particle diameter H c /D was varied from 0 to 10. The channel inclination was varied from 15° to 35° to achieve different Froude numbers before impact. A new impact model for predicting impact force exerted on the barrier with a basal clearance is presented and evaluated. Results reveal that H c ≥ 3D is capable of reducing the impact force and overflow. Findings from this study highlight the importance of considering the effects of basal clearance on the design of multiple-barrier systems.