A SYSTEM FOR DETERMINING DYNAMIC SURFACE-TENSION USING THE OSCILLATING JET TECHNIQUE

A motion analysis system based oil slow-speed video imaging was used t o develop a procedure for measuring the dynamic surface tension of liq uids at short surface ages using the oscillating jet method. Bohr's eq uation and Bechtel's inverse method were used to calculate surface ten sion from measurements of the jet waveforms. Values of surface tension determined by both methods were in good agreement with hardbook value s. Surface tensions calculated from waveforms near the jet orifice wer e found to be similar to values calculated for waveforms further from the orifice. Most agricultural sprays are mixtures of materials, not t rue solutions, and as such their surface tensions change with surface age. A method of measuring surface tensions at short surface times is essential for predictive models of the effect of adjuvants on the prop erties of agricultural sprays, especially droplet atomization and drop let rebound from plant surfaces; both of these processes are completed in less than 3 ms.