'parallel direction' is correct and usable in written English.
You can use it to describe something moving in a line that is parallel to another line. For example, "The trains moved in a parallel direction on their respective tracks."
РПЦ категорически против бородатых мужиков в платьях! pic.twitter.com/b1TLmsRI4s "Unfortunately, the legal and cultural spheres are moving in a parallel direction, to which the results of this competition bear witness".
It was found that on sliding in the anti-parallel direction a more significant degradation takes place than in the parallel direction.
The pitch angle 0 deg. is the parallel direction toward the Moon.
The one-dimensional structures were densely packed, and each nanowire lay in a parallel direction.
Compressive strength of monolith in parallel direction is around twice as much as perpendicular direction.
Bronchial lacerations have a parallel direction to the bronchial cartilaginous ring [43] and commonly cause pneumomediastinum and pneumothorax.
(e) S-wave velocity difference between trench-parallel direction Vs,tp and trench-normal direction Vs,tn.
The extension originates open fractures oriented in the trench-parallel direction, as estimated by seismic anisotropy (Figure 2d,e).
Therefore, the principal stress is locally oriented in the trench-parallel direction around the WBSF (red zone in Figure 4b).
However, the long-period spectral energy seen along the strike-parallel direction is most likely caused by permanent tectonic displacement.
(2) The strike-slip motion caused by oblique plate subduction could have contributed to the generation of the continuous mega-splay fault system in the trench-parallel direction.
