"relation exists between" is correct and usable in written English.
You can use it to describe the connection or link between two things. For example, "There is a strong relation exists between job satisfaction and employee engagement."
What relation exists between FEs and geomagnetic storms?
An analogous relation exists between any pair of canonically conjugate variables, such as energy and time.
A direct relation exists between saturation of the reaction atmosphere and the kinetics of carbothermal reduction.
Results show that a complex relation exists between PCM and TCE volume percentages.
A power-law relation exists between the convection flow rate and the dimensionless vibration velocity.
The objective of this study was to assess whether a relation exists between Poaceae evolution and root-associated diazotroph community of the resulting plant genotypes.
Refinement methods also allow us to subsequently compare two systems to see if a refinement relation exists between the two.
The S-N curves indicated that power-function relation exists between stress levels and fatigue life of PC.
During the early 20th century, pharmacologists became aware that a relation exists between the chemical structure of a compound and the effects it produces in the body.
A similar relation exists between CEO leisure consumption and firm market capitalization, which suggests that shareholder wealth is also negatively affected by the time CEOs spent on the fairways and greens.
A positive linear relation exists between the mass flow rate of transpiration water and the thickness of water film under constant feedstock parameters conditions.
