def apply_U(disp_vector, coord, factor):
    """ Apply displacement to coordinates. 

    Args:
        disp_vector (:obj:`numpy.array`): Displacement.
        coord (:obj:`numpy.array`): mesh coordinates.
        factor (:obj:`float`): Factor to deform the mesh.
    
    Returns: 
        Displaced mesh coordinates.
    """
    new_coord = coord.copy()
    new_coord[:, 1:] += disp_vector * factor
    return new_coord