Valve assembly

Valve assembly 100 comprising a cage 104 in fluid connection with an inlet 102, and a plug 108. The cage 104 comprises a first portion 104A comprising a first port 106A in a cage wall 105 for allowing fluid flow therethrough in a first mode of operation, and a second portion 104B comprising a second port 106B in the cage wall for allowing fluid flow therethrough in a second mode of operation. The second port 106B is arranged to increase turbulation when the fluid flows through the second port relative to through the first. The plug cooperates with and is moveable relative to the cage between the first and second modes of operation. The second port may be tangential to the cage wall, be curved, comprise a nozzle shaped structure, its diameter may narrow in the fluid flow direction, and comprise one or more baffles. The first port may be perpendicular to the cage wall and be straight. The plug may have a peripheral wall having first and second portions with respective first and second ports for alignment with the first and second ports of the cage. Also claimed is a pumped hydro energy storage system 600 comprising the valve assembly.