why don't you make an intermediate step and then store only the required component. Store ncap components in 2/3 UDM and then recall the gradient .. take the required component only

This is the understanding of the above. Please correct me if I'm wrong.nGet the x and y components of the unit vector ncap and store them in 2 separate UDS (UDS1 and UDS2 respectively).nGet the x-component gradient of UDS1 as UDSG1[0] and y-component gradient of UDS2 as UDSG2[1]. Add the terms UDSG1[0] and UDSG[1] to get the term ∇⋅nĖ‚.nIs the above approach what you suggested? If it is right, could you please suggest on how to obtain the x and y component of ncap separately? Would the commands ncap[0] and ncap[1] work?n