Blade-vortex interaction (BVI) is a significant aerodynamic phenomenon for rapidly developed electric vertical takeoff and landing aircraft, which generates high-amplitude noise when a rotor blade passes tip vortices. In this work, we experimentally investigate effects of vortex dynamics on rotor aeroacoustics during BVI in edgewise flows at a low Reynolds number (Re) range from $3.9\times 10^4$ to $1.0\times 10^5$, and over a practical advance ratio ($\mu$) range from 0 to 0.5, using anechoic wind tunnel tests. Thrust and power coefficients exhibit a linear relationship with $\mu$. The BVI process can be categorized into three flow regimes based on difference in vortex dynamics, each with distinct tonal and broadband noise characteristics. In regime 1 ($\mu \lt 0.1$), the interaction between the vortex and the blade boundary layer is dominant, with viscous effects on the blade surface, resulting in multiple harmonics tones over a wide frequency range. Amplitudes of high-order tones reduce with increasing $\mu$ due to downstream convection of small-scale turbulence. In regime 2 ($0.1\lt \mu \lt 0.23$), the blade interacts with the vortex shear layer, and the pressure gradient due to the leading edge becomes a primary factor during BVI. In regime 3 ($\mu \gt 0.23$), the blade directly passes through the vortex centre. Here, BVI-related tones at the middle frequency range further increase with increasing $\mu$, while spectra exhibit a broadband nature at high frequencies. Across various flow regimes at low Re, the broadband noise can be scaled using the law of $\mu ^kM_{\mathit{tip}}^5$, where $k$ is a constant determined in different flow regimes and $M_{\mathit{tip}}$ is the tip Mach number.