Thermal Wavelength Measurement of Nanofluid in an Optical-Fiber Thermal Wave Cavity Technique to Determine the Thermal Diffusivity

Figure 5

The typical behavior of the Ln amplitude and the phase as a function of the cavity length for the distilled water, at 6.73 Hz, (a) the plots of logarithmic amplitude and (b) the phase versus the cavity length, and (c) the plot of phase versus the cavity length; the half thermal wavelength was directly calculated by obtaining the cavity length between two experimental data sets; the phase equals () and the phase equals (0).

(a)

(b)

(c)