Simple system for fluid flow visualization and measurement using a chronophotographic technique
Abstract
A delay, split-timer circuit is described for use in streak photography. The unit provides the capability for relatively simple yet accurate flow visualization where conventional methods of visualization are not applicable due to high flow velocities. The basic system uses four timers and two separate strobe flashes. One timer allows synchronization with any event. Another timer controls the split time between discharges of the two strobes. By photographically recording two instantaneous positions of particles in a flow, one can draw pathlines of the particles, allowing a qualitative understanding of the flow. Delay and split times can be varied linearly (within 0.75%) to accommodate different flow rates (split times) and synchronization (delay time). The circuit design described yields predictable and repeatable time periods (to 1.5%) and is easily calibrated. To demonstrate the technique the timer was used to study steady-state secondary flows in curved ducts of square cross section and the oscillatory flow field in the tongue region of an industrial centrifugal pump.
- Publication:
-
Review of Scientific Instruments
- Pub Date:
- December 1986
- DOI:
- 10.1063/1.1138993
- Bibcode:
- 1986RScI...57.3066K
- Keywords:
-
- Chronophotography;
- Flow Measurement;
- Flow Visualization;
- Streak Photography;
- Calibrating;
- Centrifugal Pumps;
- Ducted Flow;
- Flow Distribution;
- Flow Velocity;
- Oscillating Flow;
- Two Phase Flow;
- Instrumentation and Photography