I am currently in the process of creating a heat budget model to compute stigma surface temperature. Stigmas are part of the reproductive organ of a flower (which in my case are flowers of orchards). I've attached a picture to show how it looks like. The stigmas are the white shaped bits that are popping out of the flower center. (picture not taken by me, https://thumbs.dreamstime.com/z/white-fruit-flowers-spring-beautiful-cherry-petals-anthers-stigma-branch-orchard-early-sunny-day-ready-109463924.jpg).

These things are hyper small, like in the fractions of the mms. Still, I've decided to simply consider the entire organ as if it only had 1 stigma and compute a budget for that one specifically. I consider this stigma as a cylinder and perform the necessary calculations there. My question is hence the following: would neglecting the other stigmas and only considering one would have a significant impact on the evaluation of drag and convection resistance? I am asking this because for objects of such small size, the turbulence they must generate must be so small, that I feel like the turbulence created by one stigma would not effect the others, but I'd like to know the thoughts of other people who have more knowledge than me on this matter.

I am a meteorologist by formation so I still have lots to learn in terms of understanding the mechanics of turbulence, but I have a fundamental grasp at it .

Thank you!


2 Answers 2


I know this question was asked over a year ago, but this popped into my feed and I wanted to put my two cents in since this seems very interesting. I would consider analyzing the stigmas as an array (not neglecting the other stigmas), similar to how heat transfer in pin/fin arrays are analyzed. You will probably need to make some assumptions as to the configuration of the array (i.e. staggered rows, straight rows, etc). There are tons of correlations available for heat transfer and fluid flow around arrays of fins. Here is a source showing the heat transfer equations for pins. http://thegateacademy.com/files/wppdf/Heat-transfer-through-fins.pdf Heat Transfer books by Cengel and Incropera have sections on analyzing heat transfer in pins/fins.


Admittedly fascinating subject.

If heat model scope scale is smaller than say a 5mm cube, then you will be reasonably safe to ignore other Stigmas.

However at that fine level, you should at least acknowledge the curvature of the stem and the textured spherical top.

The curve of the stem will encourage spirals of upward draft and the top will seem to current bigger than its actual size.

If you where to consider the entire bunch of stigmas then it will behave more like a heat sink.

  • $\begingroup$ I have indeed pondered about the spherical top component, but the notion of curvature didn't occur to me, thanks for pointing that out. I am confused about what you mean when saying that considering the bunch of stigmas would change the outlook of the system. Perhaps not the best question to ask, but would it be eazier for me to consider the system as a whole than just looking at a single component? Thanks! $\endgroup$ Feb 22, 2019 at 19:33
  • $\begingroup$ @MorningGlory, its just because there is much research and experiments on heat-sinks. It is at least worth looking into. $\endgroup$
    – kamran
    Feb 22, 2019 at 20:36

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