Reflected continuously tunable acoustic metasurface with rotatable space coiling-up structure

•We propose a new design for continuous tunable acoustic metasurface.•The unit of metasurface is a segment of rotatable space-coiling structure.•We utilize advantage of the anisotropic properties of the unit.•The even-order standing wave modes in waveguide can be used.•A model is proposed to analysis and give a theoretical guidance.