add the Long kernel

[slayoo]

CC: @yoctoyotta1024 @emmacware

[yoctoyotta1024]

Here also is the Simmel et al. 2002 paper which parameterises the Long Kernel: https://www.sciencedirect.com/science/article/pii/S0169809501001314 (equations 11-14)

and here is CLEO's implementation of it: https://github.com/yoctoyotta1024/CLEO/blob/13e57f71b433c71493ad41a62c92073cd0e69f92/libs/superdrops/collisions/longhydroprob.cpp#L30

(+ terminal velocity here: https://github.com/yoctoyotta1024/CLEO/blob/13e57f71b433c71493ad41a62c92073cd0e69f92/libs/superdrops/terminalvelocity.cpp#L58)

[slayoo]

thank you @yoctoyotta1024 !

[github-actions]

Stale issue message

[slayoo]

#1785 has just been merged!
kudos @ekdejong

[ekdejong]

Woohoo! Thanks for the help, Sylwester! From: Sylwester Arabas ***@***.***> Date: Tuesday, March 24, 2026 at 7:00 AM To: open-atmos/PySDM ***@***.***> Cc: de Jong, Emily Katherine ***@***.***>, Mention ***@***.***> Subject: Re: [open-atmos/PySDM] add the Long kernel (Issue #1714) [https://avatars.githubusercontent.com/u/89685?s=20&v=4]slayoo left a comment (open-atmos/PySDM#1714)<https://urldefense.us/v3/__https://github.com/open-atmos/PySDM/issues/1714*issuecomment-4118057358__;Iw!!G2kpM7uM-TzIFchu!x9XZvH5EQ87esb76-M4JKFoHmgcOoI2sFsTni4LV8zZ8W7YqJGoOszLZ3uOcIlJPXoC7KfAFfkMv0Gv2lsnlxx3KFw$> #1785<https://urldefense.us/v3/__https://github.com/open-atmos/PySDM/pull/1785__;!!G2kpM7uM-TzIFchu!x9XZvH5EQ87esb76-M4JKFoHmgcOoI2sFsTni4LV8zZ8W7YqJGoOszLZ3uOcIlJPXoC7KfAFfkMv0Gv2lskNFMb2sA$> has just been merged! kudos @ekdejong<https://urldefense.us/v3/__https://github.com/ekdejong__;!!G2kpM7uM-TzIFchu!x9XZvH5EQ87esb76-M4JKFoHmgcOoI2sFsTni4LV8zZ8W7YqJGoOszLZ3uOcIlJPXoC7KfAFfkMv0Gv2lsnzsJVmcw$> — Reply to this email directly, view it on GitHub<https://urldefense.us/v3/__https://github.com/open-atmos/PySDM/issues/1714?email_source=notifications&email_token=AOYOQCYRG6EJJZ3GAB5NI4D4SKBGDA5CNFSNUABFM5UWIORPF5TWS5BNNB2WEL2JONZXKZKDN5WW2ZLOOQXTIMJRHAYDKNZTGU4KM4TFMFZW63VHNVSW45DJN5XKKZLWMVXHJLDGN5XXIZLSL5RWY2LDNM*issuecomment-4118057358__;Iw!!G2kpM7uM-TzIFchu!x9XZvH5EQ87esb76-M4JKFoHmgcOoI2sFsTni4LV8zZ8W7YqJGoOszLZ3uOcIlJPXoC7KfAFfkMv0Gv2lslDKlm_JQ$>, or unsubscribe<https://urldefense.us/v3/__https://github.com/notifications/unsubscribe-auth/AOYOQC7LX5W3266KAXUXNBT4SKBGDAVCNFSM6AAAAACGY4S7IWVHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHM2DCMJYGA2TOMZVHA__;!!G2kpM7uM-TzIFchu!x9XZvH5EQ87esb76-M4JKFoHmgcOoI2sFsTni4LV8zZ8W7YqJGoOszLZ3uOcIlJPXoC7KfAFfkMv0Gv2lsnRy1oHPA$>. You are receiving this because you were mentioned.