apostrophe rules in academic writing

I've been reading papers from nucleate boiling mechanics and related areas, and I keep being puzzled by the usage of apostrophes. For example, we talk about bubbles:

Numerical simulations of the bubble dynamics in viscoelastic media showed varying degrees of success in accurately predicting the observations.

Here we see bubble dynamics with no apostrophe. Then on the next page:

Visualization of the multiflash imaging technique with timing diagrams of the variable flash sequences used during each phase of the bubble’s evolution with example images.

Here we have bubble's evolution, apsotrophe present. Or, another example:

The assumption of material homogeneity in the model is likely also not valid for agarose gels, particularly in the early parts of a bubble’s lifetime.

So is it equally correct to say the bubble's size and the bubble size, the heater's tempetature and the heater temperature, etc.?

Please help me sort it out. Many thanks to all who had enough patience to read all this.

Solution 1:

You're seeing a mix of noun adjuncts, where the word "bubble" is used to modify another word, and possessives, where is said to belong to a bubble.

Bubble dynamics is a discipline within fluid mechanics. To name the field, we need to have a general, described term like this. "A bubble's dynamics" would be talking about the motion of a particular bubble (and would not match with the actual way we use the term 'dynamics' within engineering science). You will seldom see possessives used to describe a topic, abstractly.

The possessive is used in "each phase of the bubble's evolution" to refer to the phases belonging to a particular bubble. Thus, the bubble in question has an evolution. Though sometimes this could refer to a characteristic bubble rather than a concrete example of a bubble, the possessive would not be used to name the topic examining bubbles evolving: that topic would be bubble evolution.