The parameter 1 1 − β 4 {\displaystyle {\frac {1}{\sqrt {1-\beta ^{4}}}}} is often referred to as the velocity of approach factor[6] and multiplying the coefficient of discharge by that parameter (as was done above) produces the flow coefficient C {\displaystyle C} . Methods also exist for determining the flow coefficient as a function of the beta function β {\displaystyle \beta } and the location of the downstream pressure sensing tap. For rough approximations, the flow coefficient may be assumed to be between 0.60 and 0.75.