Developing a virtual physical system for vortex-induced vibration studies of a bluff body

• A virtual physical system (VPS) is developed to replace the actual physical systems and can arbitrarily and accurately control and edit the physical parameters. • The recursive Duhamel integral method (DIM) with unconditional stability is preferred and demonstrated to be suitable in the VPS control system. • The delay compensation and inertial force elimination methods are investigated and proposed to solve the inevitable critical problem encountered in VPS. • The re effects on VIV response, and corresponding hydrodynamics are preliminarily revealed through the model tests at high and low re by VPS. A virtual physical system (VPS) for VIV studies of a bluff body is developed to replace the actual physical systems. It can arbitrarily and accurately control and edit the physical parameters, including mass, damping ratio and spring stiffness, specifically for the mass-spring-damper system. The recursive Duhamel integral method (DIM) with unconditional stability was used for the VPS control system, addressing real-time noise filtering problem and simplifying the system as a single input and single output (SISO) one. Delay compensation and inertial force elimination methods were investigated and proposed to overcome the crucial unwanted damping effects. An experimental facility for VIV model tests by VPS was manufactured, and the bluff body model with a measurement system was specially designed to accurately sense the hydrodynamic force during VPS operation. Systematic verification experiments for parameter editing and control of an actual physical target system were conducted, showing that the VPS can reproduce the equivalent spring-damper-mass system in high fidelity with an accuracy error of less than 5 %. VIV model tests for a bluff body at Reynolds numbers ( Re = UD / υ , where U is the flow velocity, D represents the diameter of cylinder model, and υ is the kinematic viscosity coefficient) of 5.7E4 and 2.3E5 were performed using the VPS experimental facility, presenting well-Repeated VIV responses at low Re and unexpected VIV response with a large amplitude of 2.4 D at high Re , which can cause severe fatigue damage for relevant structures. The present VPS will provide promising and powerful experimental tools for VIV studies of a bluff body to reveal the related sensitive parameter effects.