Abstract: The faraday wave of the low- viscosity silicon oil excited by vertical sinusoidal oscillation at low frequencies is studied from experimental and theoretical aspects. A series of clear standing wave patterns（ 2- crest pattern to 8- crest pattern）,especially the stars- shaped one have been observed. Systematic study shows that the waves belong to subharmonic resonance with frequency of half the excitation frequency. The dispersion relation of the observed surface wave can be described by the inviscid theory and gravity is the dominant restoring force. The standing wave patterns are classified by the number of the wave crest. In experimenting with the increase of the driving frequency,the wave patterns become complicated and show up as the increase of the wave crest number,while the corresponding amplitude decreases. This experimental phenomenon is explained well by analyzing the wavelengths and excitation threshold of the different patterns of the standing waves. The study in this paper has certain reference significance to the research of the surface wave of a fluid in a rigid container due to external excitation.

Key words: faraday wave, subharmonic resonance, viscid fluid