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ID Project Category View Status Date Submitted Last Update 0003492 OpenFOAM Bug public 2020-05-11 08:34 2020-05-22 08:42 FoamerLY will normal minor always resolved fixed GNU/Linux Ubuntu 14.04 dev 0003492: The formula in the OF is inconsistent with the Rosin-Rammler distribution theory formula The formula used to calculate CDF (Cumulative Distribution Function) is at line 31 in RosinRammler.H (https://github.com/OpenFOAM/OpenFOAM-7/blob/master/src/lagrangian/distributionModels/RosinRammler/RosinRammler.H) The CDF is now calculated as: cumulative model=(1.0-exp(-((x-d0)/d)^n))/(1.0-exp(-((d1-d0)/d)^n)); where d0 and d1 are the minimum and maximum diameters of particles, respectively; d is the Rosin-Rammler representative diameter and n is the Rosin-Rammler exponent. They are all constants. However, according to Atomization and Sprays and Ansys Fluent Users Guide Release 19.0 the theoretical formula of Rosin-Rammler distribution is as follows: cumulative model=(1.0-exp(-(x/d)^n+(d0/d)^n))/(1.0-exp(-(d1/d)^n+(d0/d)^n)); With the same parameters, these two formulas may get different solutions. Based on the coefficients in the OpenFOAM-7/tutorials/lagrangian/sprayFoam/aachenBomb/sprayCloudProperites#L139, We find that when the values of d0 and d1 are very different, the two curves of CDF are similar (see Figure 1). However, when the difference between the two values is not that large, the two curves began to show differences (see Figure 2). Accoding to the Rosin-Rammler distribution parameters (Fig. 3) adopted in 'Large eddy simulation of high-velocity fuel sprays: studying mesh resolution and breakup model effects for spray A', there are obvious differences between the two CDF curves (Fig. 4). No tags attached.

#### Issue History

2020-05-11 08:34 FoamerLY New Issue
2020-05-11 08:34 FoamerLY File Added: figure 1.png
2020-05-11 08:34 FoamerLY File Added: figure 2.png
2020-05-11 08:34 FoamerLY File Added: figure 3.jpg
2020-05-11 08:34 FoamerLY File Added: figure4.png
2020-05-12 09:48 will Note Added: 0011337
2020-05-12 09:49 will Note Edited: 0011337
2020-05-14 09:57 FoamerLY File Added: Equation 1.png
2020-05-14 09:57 FoamerLY File Added: Equation 2.png
2020-05-14 09:57 FoamerLY File Added: Equation 3.png
2020-05-14 09:57 FoamerLY File Added: Equation 4.png
2020-05-14 09:57 FoamerLY Note Added: 0011341
2020-05-14 19:26 will Note Added: 0011344
2020-05-18 11:52 FoamerLY File Added: picture 5.png
2020-05-18 11:52 FoamerLY File Added: Table 2.png
2020-05-18 11:52 FoamerLY File Added: picture 6.png
2020-05-18 11:52 FoamerLY File Added: Table 3.png
2020-05-18 11:52 FoamerLY Note Added: 0011352
2020-05-19 12:44 will Note Added: 0011358
2020-05-21 07:34 FoamerLY Note Added: 0011362
2020-05-22 08:42 will Assigned To => will
2020-05-22 08:42 will Status new => resolved
2020-05-22 08:42 will Resolution open => fixed
2020-05-22 08:42 will Fixed in Version => dev
2020-05-22 08:42 will Note Added: 0011363