BOSSIO CASTRO, A. Lagrangeovský model pohybu kavitační bubliny [online]. Brno: Vysoké učení technické v Brně. Fakulta strojního inženýrství. 2019.
In his master thesis Alvaro Bossio created a numerical Lagrangian model to track bubble trajectory in cavitating flow. His work has practical impact in one of the projects currently ongoing at our department, which is aimed on application of hydrodynamic cavitation for chemical residuals removal from waste water. The numerical model is based on alternative fomulation of classical Rayleigh-Plesset equation, which is non-linear equation describing bubble wall motion subjected to alternating surrounding pressure field. He coupled this equation with the second Newton law, creating a complete system to track the bubble motion. He successfully applied the final Matlab code on tracking the bubble in cavitating Venturi tube and orifice, geometries that we use in our experiments. Alvaro Bossio was working responsibly and vigorously from the beginning and we had many fruiful discussions regarding topic of his thesis. Apart from this he also studied lots of scientific papers in this field. From the formal side there is one serious drawback – the thesis conclusion is missing. Despite this fact I highly appeciate his work and it is my pleasure to recommend his thesis for the defense.
| Kritérium | Známka | Body | Slovní hodnocení |
|---|---|---|---|
| Splnění požadavků a cílů zadání | A | ||
| Postup a rozsah řešení, adekvátnost použitých metod | A | ||
| Vlastní přínos a originalita | B | ||
| Schopnost interpretovat dosažené výsledky a vyvozovat z nich závěry | A | ||
| Využitelnost výsledků v praxi nebo teorii | A | ||
| Logické uspořádání práce a formální náležitosti | C | ||
| Grafická, stylistická úprava a pravopis | A | ||
| Práce s literaturou včetně citací | B | ||
| Samostatnost studenta při zpracování tématu | A |
The proposed thesis describes the dynamics of a cavitation bubble submerged in a steady flow and in static flow affected by a uniform oscillatory pressure field, respectively. The thesis is divided into three parts. The first contains mathematical models including several modifications. Second part is devoted to the theory of differential equations and specific numerical methods for ODE solution, and in the last part, the above mentioned study-cases are elaborated in detail. Even though the thesis is well written, the main objection is the absence of proofs of theorems and lemmas in the second part and missing reference to appropriate literature with correct proofs. This is especially necessary regarding those theorems modified by the student (note that some of the modifications are unnecessary and correctness of the rest may be questioned, eg. Lemma 3.1.1, Theorem 3.2.2 or Theorem 3.2.3. Also Theorem 3.3.1 is not Lax equivalence theorem but Dahlquist equivalence theorem. Reference [44] which appears on several places in the text, was impossible to find in any database! Symbol f is not specified in the assertion (2.27) and „gamma“ is undefined in (3.67). The text contains further typos and inaccuracies, but their number is appropriate to the range of the thesis. The last sections contains good description and discussion of two study-case models which was the main objective of the thesis. Therefore I recommend the thesis for the defense with classification B/very good.
| Kritérium | Známka | Body | Slovní hodnocení |
|---|---|---|---|
| Splnění požadavků a cílů zadání | A | ||
| Postup a rozsah řešení, adekvátnost použitých metod | A | ||
| Vlastní přínos a originalita | C | ||
| Schopnost interpretovat dosaž. výsledky a vyvozovat z nich závěry | A | ||
| Využitelnost výsledků v praxi nebo teorii | B | ||
| Logické uspořádání práce a formální náležitosti | C | ||
| Grafická, stylistická úprava a pravopis | B | ||
| Práce s literaturou včetně citací | D |
eVSKP id 117229