Method for identifying slow transient variations and/or local spatial variations in vehicle related fluid dynamic conditions of a physical property in a set of data points. The method includes obtaining a first set of data points, calculating a temporal filtered value of the representation of the physical property for at least a portion of the first set of data points distributed over the total time period, combining at least a portion of the calculated temporal filtered values to obtain a second set of data points, and analysing in time sequence the second set of data points over at least a portion of the total time period.