How well does the theoretical model predict the measured force for the symmetric and asymmetric impact surfaces?

1) First step would be determining the measured force through your experiment for the Reaction force of the both the surfaces on the jet of fluid stream. The value would be R_actual.

2) Second step is to compute the Reaction force by the theoretical model which takes an assumption of no kinetic energy loss from a jet of fluid stream impinging on to the surfaces i. e the velocity before and after impact is the same. This value would be R_theoratical.

3) Step Three would be to compare the actual and theoretical values of Reaction forces exerted by the surfaces by the following formula:

% Difference = [ (R_actual - R_theoratical) / R_actual ] * 100

4) The standard followed is that a theoretical model must predicts within 10% uncertainty about the actual value obtained from experiment.

5) If the difference is greater than 10% it means that the assumption of no Kinetic Energy Losses was not feasible and should be included in the model for accuracy.