( ( ( ( ( ( In order ) ( to ( measure ( the velocity ) ) ) ) ( images ( were ( taken ( of ( ( two bubbles ) ( ( rising ( in ( the pipe ) ) ) ( until coalescence ) ) ) ) ) ) ) ) and ) ( ( ( the velocity ) ( as ( ( a function ) ( of ( the ( separation distance ) ) ) ) ) ) ( was ( ( determined directly ) ( from ( the film ) ) ) ) ) ) . )
(ROOT (S (S (SBAR (IN In) (NN order) (S (VP (TO to) (VP (VB measure) (NP (DT the) (NN velocity)))))) (NP (NNS images)) (VP (VBD were) (VP (VBN taken) (PP (IN of) (NP (NP (CD two) (NNS bubbles)) (VP (VBG rising) (PP (IN in) (NP (DT the) (NN pipe))) (PP (IN until) (NP (NN coalescence))))))))) (CC and) (S (NP (NP (DT the) (NN velocity)) (PP (IN as) (NP (NP (DT a) (NN function)) (PP (IN of) (NP (DT the) (NN separation) (NN distance)))))) (VP (VBD was) (VP (VBN determined) (ADVP (RB directly)) (PP (IN from) (NP (DT the) (NN film)))))) (. .)))
In order to measure the velocity images were taken of two bubbles rising in the pipe until coalescence and the velocity as a function of the separation distance was determined directly from the film.
(ROOT (S (NP (NP (NNP Distance)) (PP (IN over) (NP (NP (NN time)) (PP (IN in) (NP (DT a) (VBN given) (NN direction)))))) (VP (VBZ determines) (NP (NN velocity))) (. .)))