In allusion to the vibro-acoustic experiments of cavity in wind tunnel

taking typical elastic cavity as the research object

dimensional analysis was adopted to establish the similitude relations of structural natural frequencies and dynamics for complete geometric similarity model. Combining the structural finite element theory

the similitude relations of structural natural frequencies and dynamics for incomplete geometric similarity model were established by introducing the complete geometric similarity model as intermediate model. Numerical simulations of natural frequencies and dynamics of scale-down elastic cavity model were carried out. According to the numerical results of scale-down model

the dynamic response results of full-scale model were predicted by the proposed similitude relations. Results showed that the predicted dynamic response curves were in coincidence with the actual numerical results

which verified the feasibility of the proposed similitude relations and also provided a theoretic guidance for structural design and vibro-acoustic experiments of scaled down elastic cavity model with similar dynamics. The analysis method of the established similitude relations can be applied to complex thin-wall structures.