The size of the flow velocity of the fluid at each point proximal velocity shell (PIS) is equal and identical to (v R) flow rate reference value, the present invention forms the viewing portion of the fluid to move to (B) The method and apparatus for three-dimensional derived adaptive proximal velocity shell proximal flow convergence region is the (PIS),: and locally in the peripheral part a) viewing portion of (B) A providing a flow velocity measurement result of the dispersion, measured indicates the direction component of the at least one flow rate localized fluid in the measuring direction of the respective flow entire process, b) the flow focussing region substantially at least In the method, such as to penetrate the (APIS k = o) approximate surface basis, as (PIS) preparing a (APIS k = o) approximate surface, c) approximate surface proximal portion constant velocity shell of initial (APIS a step of identifying a (v kJ) flow rate measurement of each approximation point a step of establishing approximate points of multiple (a kj) to k) above, d) for each (a kj), e) the approximate point ( as a function of the (n kJ) surface normal of each (v kJ), the measurement direction of the respective (m kJ), to calculate (vk kJ) Flow rate corrected flow velocity measurements in a kj), where it is indicated By comparing the flow rate reference value (v R) and (vk kJ) flow rates and process, it is f) correction, and a step of identifying a (K kJ) correction direction, by g) case, the correction in each direction (K In kj), a step of transferring to a new position (a kj) approximation points, to close at least to a new position h) the approximate point (a kj), to obtain the (APIS k + 1) new approximation surface and a step of variation of (APIS k + 1) until small enough new approximation surface of comparing the process, i) the old approximation and the surface (APIS k), the sequence repeats h) from step c), the apparatus and method about.本発明は、近位部等速シェル(PIS)の各点における流体の流速の大きさが流速
