**3.3 High-speed camera estimate**

**Structure velocity m**ð Þ¼ *=***s**

*Vortex Dynamics Theories and Applications*

ity in two-phase flows is shown in **Figure 6**.

**3.2 Manual time series analysis**

using Eq. (22).

**Figure 7.**

**Figure 8.**

**208**

*Camera control software window used to estimate velocity.*

**Distance between centres**

**electrodes for two planes m**ð Þ

**Time delay s**ð Þ (22)

**of measurement**

The schematics of the ECT Sensor signals generation for measurement of veloc-

The structure velocity can be obtained manually by estimating the time displacement of output signals from both planes 1 and 2 via the peaks of the time series plots for both planes. Since the distance between the centres of the measurement electrodes for both planes are known, the structure velocity is hence computed

The time displacement from the time series data of both planes 1 and 2 used in the calculation of the structure velocity alongside with distance between centres of

*Cross-sectionally averaged void fraction time series for plane 1 and 2 at a superficial gas velocity of 0.02 m/s.*

The camera control software of the Phantom High-Speed Camera can be used to obtain an estimate of the structure velocity. This is done via a playback in which the distance covered by the bubble at a given time is computed which gives a corresponding value for the velocity. A typical window of the camera control software is shown in **Figure 8**.
