Model railroad type example Sn3.5 is as follows, S (scale) being the prefix to n (narrow gauge) followed by 3.5 (prototype track gauge in feet), 3 and 1/2 feet, or 42 inches, which in Sn3.5 equates to actual modeling track width of .649 - .672 thousandths, 16.5 - 17.1 mm.
Definition of harmonic. 1  1a : overtone; especially : one whose vibration frequency is an integral multiple of that of the fundamentalb : a flutelike tone produced on a stringed instrument by touching a vibrating string at a nodal point.
The resonance frequencies of the fixed-fixed string are harmonics (integer multiples) of the fundamental frequency (n =1). The vibrational pattern (mode shape) of the string at resonance will have the form.This equation represents a standing wave. There will be locations on the string which undergo maximum displacement (antinodes) and locations which to not move at all (nodes).he vibrational pattern (mode shape) of the string at resonance will have the form. This equation represents a standing wave. There will be locations on the string which undergo maximum displacement (antinodes) and locations which to not move at all (nodes).