"small fluctuation" is correct and usable in written English.
You can use it to refer to a minor change in something over time, usually something that repeatedly changes by a small amount. For example, "We observed a small fluctuation in temperature over the course of the experiment."
"It will be a small fluctuation, sure, but it's not going to drop 10 or 20 percent".
Estimates of the star density measured across the arms of spiral galaxies and into the interarm regions show that the large-scale spiral structure of a galaxy of this type is, at least in many cases, represented by only a relatively small fluctuation in star density.
A small fluctuation is observed at elevated temperature for endurance and retention test.
All growth parameters were real-time monitored and controlled to provide a stable environment with small fluctuation for crystal growth.
It makes the synchrosqueezing difficult to accurately estimate IFs with highly oscillating rate but small fluctuation amplitude.
In contrast, the performance of Algorithm 2 has a small fluctuation for different K t, K r and K combinations.
Considering the VBLs as quasiparticles, examine now the small fluctuation displacements of VBL from the equilibrium position.
This happens because small fluctuation of results in larger throughput change, if all the users have higher SNR levels.
The inverse filter may amplify a small fluctuation in the RTFs and may cause large distortions in the filter's output.
Initially, the small fluctuation in electric current around the electric cycle (50 Hz) is reduced in order to reinforce cyclostationarity.
A small fluctuation in S-wave energy at lapse times between P-wave onset and S-wave onset is found.
