"rough relations" is correct and usable in written English.
It is often used to refer to strained relationships, such as between two countries. For example: The two countries had rough relations in the past, but fortunately they are now on better terms.
Utilizing computational fluid dynamics, the present method establishes a rough relation between the boundary wind velocity and the wind velocity at the anemometer, guided by which a feedback process is conducted to search for the boundary velocity matching the measurement of the anemometer.
Rough relation between VF and PE.
As the numbers of tRNA genes vary slightly from one genome assembly to another, and since we assume a rough relation between tRNA gene copy numbers and tRNA abundances, small variation in tRNA gene copy numbers of synonymous codons have no meaning.
Her duet from "Pieces of Trust" (1987 and 1989) has more bite to it, thanks in part to a Meredith Monk song that forms part of the score, and to slightly rougher gender relations.
And mezcal, tequila's rough-hewn relation, had none at all.
Azerbaijan has also hit a rough spot in relations with Turkey, which is trying to reconcile with Armenia, its neighbor.
Tensions are also highlighted in an economic dispatch, written by the US ambassador to Beijing last January, warning of a "rough" year for relations between the two countries and accusing China of hubris.
Mrs. Clinton's diplomacy — bolstered by Gen. Martin E. Dempsey, the chairman of the Joint Chiefs of Staff, and David H. Petraeus, the director of the C.I.A. — appeared to smooth out the roughest edges in relations, according to officials from both countries.
On August 30, the Egyptian motorship Raseltin encountered rough seas in relation to Gustav, and the hull of the ship was damaged.
