Abstract: Three cylinders are arranged as an equilateral triangle, two cylinders are in tandem arrangement, and the third one is by the side of the two cylinders. The pressure fluctuations of these three cylinders has been studied. The fluctuating pressure of rear cylinder are affected more seriously by the side cylinder. The distribution curve is unsymmetrical, it has very strong fluctuating pressure at outer face and the very weak pressure fluctuating at inner side of the rear cylinder. Also, the critical spac...