Terminal velocity is an important factor, which is useful for designing different unit operations such as hydro transport and sorting of fruits. The current investigation is aimed to propose a new dimensionless model for terminal velocity of cantaloupe fruit. For this purpose, 30 fruits from three different varieties commonly known as Jana, Gerdabadi, and Shahabadi randomly were collected and, then, the physical properties, which may affect terminal velocity, were determined. On the basis of Buckingham theorem, six dimensionless groups were recognized and established to be used for dimensionless modeling of terminal velocity of cantaloupe fruit. Dependent pi‐term versus each independent pi‐term was drawn, and regression analysis was applied to draw the curves to produce linear equations, which can be used in the construction of the dimensionless model. In order to evaluate the obtained model, terminal velocity of six randomly selected fruits from each cantaloupe variety were measured and compared with the predicted terminal velocity values. A good agreement was achieved between the experimental and the predicted terminal velocities. Also, the coefficient of determination, mean bias error, and mean relative deviation of the comparison were calculated as 0.90, 7.9, and 10.35%, respectively. In this context, the obtained model can be used as an appropriate procedure for the prediction of terminal velocity of cantaloupe fruit as well as other similar fruits with good accuracy. Practical applications Development of a generalized dimensionless model describing terminal velocity of cantaloupe fruit as a function of various physical characteristics can be used in different units of food industries such as fruit compote preparation and juicer industries. It may also be used for the designation of sorting units and hydro transport of different fruits. In other words, the obtained model could be used to sketch unit operations, which involve some postharvesting activities for cantaloupe fruits.

The current investigation was devoted to determining some properties, such as physical dimensions, surface area, sphericity, density, stiffness, and terminal velocity of cucumber. For this purpose, different cultivars of cucumber which commonly consumed in Iran, namely, Nagin, Shahab, and Shahin were selected. Also, in order to propose a new model for the terminal velocity of cucumber, a dimensionless model was established. The obtained results showed that varieties of Shahab, Shahin, and Nagin had an average length of 163.4, 118.97, and 133.89 mm, respectively. Corresponding values for average diameter for varieties mentioned earlier were measured as 26.99, 57.811, and 27.59 mm, respectively. Moreover, the density determined from the measurement of mass and volume for Shahab, Shahin, and Nagin varieties were calculated as 956, 1042, and 990 kg m −3 , respectively, while the compressive and shear bio-yield point of them were reported as 628.38 and 74.094, 505.11 and 89.33, and 652.2 and 64.79 N, respectively. Additionally, the assessment of the dimensionless model, regarding the coefficient, mean relative deviation, and root means the square error of comparison between predicted and measured terminal velocity were 0.9, 0.15, and 0.013, respectively. Therefore, the obtained characteristics may be useful in the design of different unit operations of post-harvesting technologies. Practical applicationsMeasurement of physical properties of different common cucumber fruits can be accounted for as a useful tool to design the post-harvesting unit operations. Therefore, the proposed mathematical model for the description of the terminal velocity of cucumber could be approached in pickle production units. Also, the obtained properties are usable in hydro transport and sorting of the fruit.

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