I made publically available Python scripts here to calculate grain collisional velocities in arbitrary turbulence models based on our paper :

• Gong, M., Ivlev, A. V., Akimkin, V., Caselli, P., 2021, Accepted by ApJ: Impact of magneto-rotational instability on grain growth in protoplanetary disks: II. Increased grain collisional velocities

This can be viewed as an extension of Ormel & Cuzzi (2007), which can be only applied to Kolmogorov turbulence.