The Imperial Star Destroyers, parallel to the defense forces, each commence firing from their side arcs that are facing the defense ships. Description from I searched for this on

Star Wars-Capital Ships-Viceroy Star Destroyer at Galactic Voyage

This is a concept done for Star Wars. The ship was said to be used in the clone wars for cargo/transport, and was adapted from a corporate vessel.

Victory I class Star Destroyer ortho [New] by unusualsuspex on DeviantArt