The purpose of this study is to reduce the conveying velocity and power consumption in gas-solid two-phase flows. Four pieces of soft fins with different (non-uniform) lengths, which are fixed on the horizontal central plane of the inlet, are employed to self-excite the gas-solid flow. A horizontal acrylic pipe, approximately 5 m long and with an inside diameter of 80 mm, is selected as the test pipeline. The test solid materials are spherical polyethylene particles with average diameter and density of 23 mm and 978 kg/m(3), respectively. The solid mass flow rate and average gas velocity are 0.10-0A7 kg/s and 10-17 m/s, respectively. Compared with non-fin and previous uniform soft fin gas-solid flows, the minimum gas velocity, pressure drop, additional pressure drop, and power consumption are reduced when a lower gas velocity is achieved with the use of non-uniform soft fins. The highest reduction rates in power consumption and minimum velocity are approximately 5.87% and 10.04%, respectively. The particle concentration in flows with non-uniform soft fins is higher than that in the non-fin flow in the upper part of the pipe of the acceleration region and lower than those in non-fin and uniform fin flows near the pipe bottom. By employing particle image velocimetry measurement, the time-averaged axial particle velocity and fluctuating particle velocity in all non-uniform fin flows are found to be higher than those in non-fin and uniform fin flows, especially near the upper part of the pipe. (C) 2020 Elsevier B.V. All rights reserved.