An Optical System Using Moire' Patterns to Obtain Quantitative Data in a Boundary Layer

摘要

The moire' technique is extended to the measurement of refractive index gradients in air. Moire' bands produced by printers' screens separated by an air space are deviated by an index of refraction gradient. The deviation is shown to be directly proportional to the temperature and density gradients. Temperature gradients are measured along the vertical surface of a heated flat plate and compared with theoretical values. Measured values generally agree with theoretical values within 5%. (Author)