Eight decreasing adverse pressure gradient flows, and the similar regions of an initially increasing adverse pressure gradient flow, are examined in terms of the two experimentally observed half-power regions. The existing semi-empirical and analytical mean velocity profiles are examined and their range of applicability is determined in terms of the ratio of outer to inner half-power slopes. Three variations of the k-e model of turbulence are evaluated in terms of how well they predict the turbulence field in an eight degree conical diffuser. The model of Nagano and Tagawa (1990) is seen to be superior to the others. It is possible for Nagano and Tagawa’s model to yield reasonable prediction of k and E because they implemented the Hanjalic and Launder (1980) modification for the irrotational strains. However, the k-e models prediction of the Reynolds stresses is poor. / Thesis / Master of Engineering (ME)

No / The determination of velocity profiles in turbulent narrow open channels is a difficult task due to the significant effects of the anisotropic turbulence that drives the Prandtl’s second kind of secondary flow in the cross section. Due to these currents the maximum velocity appears below the free surface. This is called the dip phenomenon. The classical log law describes the velocity distribution in the inner region of the turbulent boundary layer. The Coles law and its wake function are not able to predict the velocity profile in the outer region of narrow channels. This paper relies on an analysis of the Navier-Stokes equations and yields a new formulation of the vertical velocity profile in the outer region of the boundary layer in the central cross section area of steady, fully developed turbulent flows in open channels. This formulation is able to predict primary velocity profiles for both narrow and wide open channels. This new law is a modification of the classical one, it involves an additional parameter CAr that is a function of the position of the maximum velocity ξdip and roughness height (kS).ξdip may be derived either from measurements or from an empirical equation given in this paper. A wide range of longitudinal velocity profile data for narrow open channel has been used for validating the new law. The agreement between the experimental data and the profile given by the law is very good, despite the simplification used.

Laboratory experiments were conducted to investigate the velocity and turbulence characteristics in flows through rigid vegetation. The vegetation was simulated by an array of acrylic dowels mounted to the bed of a recirculating hydraulic flume. Velocity measurements were taken in both the longitudinal and vertical directions using a one-dimensional laser doppler velocimeter (LDV). Experiments were conducted under partially submerged, fully submerged and double layer flow conditions. The term double layer flow is used to describe flows that contain two different heights of vegetation. In each experiment, velocity and turbulence intensity profiles were taken at several different locations within the array. Additional experiments were conducted to examine how bed and vegetative skin roughness influence the velocity and turbulence characteristics. Belt sander strips were glued to the bed of the flume to simulate bed roughness and adhesive sandpaper was attached to the dowels to simulate vegetative skin roughness. Finally, experiments were conducted to study sediment transport and deposition in flows containing vegetation. / Master of Science

Background: The intensity or load of a strength training exercise is commonly considered to be the most important factor contributing to muscular strength and power. Traditionally in strength training, intensity is defined as the percentage of the maximum weight that can be lifted once i.e. 1 repetition maximum. For power development exercises, the velocity can be used to measure the intensity. A linear position transducer is able to measure kinetic and kinematic variables. Velocity-based training refers to the usage of a linear position transducer to track movement velocity of an exercise and thus, using velocity, rather than load, as a measurement of intensity. Purpose: The purpose of this systematic review was to provide an analysis of the existing velocity-based training research utilizing a linear position transducer. The study also aimed to investigate the validity and reliability of different commercial linear position transducers for kinetic and kinematic measurements.   Method: A systematic review was conducted from 19 studies on velocity-based training that met the selection criteria and underwent a quality assessment. Results: It was possible to predict the 1 repetition maximum using velocity and the minimal velocity threshold was stable across different relative intensities. Performing squats at either maximal velocity, or stopping at a velocity loss of <40% could significantly improve 1 repetition maximum, increase mean velocity during a set of squats as well as vertical jump performance. Two linear position transducer were found to have excellent validity and reliability for both kinetic and kinematic measurements. Conclusion: Velocity-based training was beneficial for enhancing neuromuscular adaptions and could be used to predict the 1 repetition maximum. When using of a linear position transducer for power development, it is suggested that it is valid and reliable for both kinetic and kinematic measurements.

Introduktion: Hastighetsbaserad styrketräning är en metod där rörelsehastighet används för att styra träning, samt monitorera träningsintensitet och volym. Metoden har vuxit fram som ett komplement till traditionellt procentbaserad styrketräning. Syfte: Syftet med litteraturstudien var att undersöka effekterna mellan olika metoder av hastighetsbaserad styrketräning och dess förhållande till traditionell procentbaserad styrketräning. Metod: En strukturerad litteratursökning genomfördes i de vetenskapliga databaserna PubMed och SPORTDiscus med de primära sökorden; velocity-based training, percentage based training och training effect. En ytterligare sökning genomfördes i referenslistorna bland de artiklar som uppfyllde inklusionskriterierna. Resultat: Litteraturstudien visade att hastighetsbaserad styrketräning medförde liknande styrkeökningar som traditionell procentbaserad styrketräning. Hastighetsbaserad styrketräning medförde större ökningar i hopphöjd jämfört med traditionell procentbaserad styrketräning. Ingen av interventionerna medförde träningseffekter på sprintförmåga. Konklusion: Hastighetsbaserad styrketräning verkar vara lika effektivt för att utveckla maximal styrka men effektivare för att utveckla hoppförmåga jämfört med traditionellt procentbaserad styrketräning. Hastighetsbaserad styrketräning med lägre procentuell hastighetsförlust verkar vara fördelaktigt för att utveckla hoppförmåga medan högre procentuell hastighetsförlust verkar vara fördelaktigt för att utveckla muskelhypertrofi. / Introduction: Velocity based training refers to a method where movement velocity is used to regulate strength training and monitor training intensity and volume. In addition, velocity based training could be considered as a complementary method to traditional percentage based training. Purpose: The aim of the literature review was to investigate the effects of different velocity based training methods and their relationship to traditional percentage based training. Method: A structured literature search was conducted in the scientific databases PubMed and SPORTDiscus with the following search terms; velocity-based training, percentage based training and training effect. A further search was conducted in the reference list among articles that met the inclusion criteria. Results: The literature review shows that velocity based training leads to similar gains in maximal strength as traditional percentage based training. However, velocity based training leads to greater gains in jump height compared to traditional percentage based training. Sprint ability showed no clear outcome following any of the interventions. Conclusion: Velocity based training seems to be just as efficient in developing maximal strength but more efficient in developing explosive strength such as jump height compared to traditional percentage based training. In addition, velocity based training with lower velocity loss thresholds may be more beneficial to improve jump height, whilst higher velocity loss threshold may be more beneficial to develop muscle hypertrophy.

Load-velocity relationships may vary between people of different strength levels and across different loads. The purpose of this dissertation was to investigate how external loads influence the velocity characteristics of the back squat exercise, and the influence of strength on these variables. Healthy male students with a history of resistance training completed repetitions at specified intensities of their estimated one-repetition maximum (1RM) until they reached 1RM. Back squat 3D motion analysis was captured using four Vicon T010 cameras (Vicon Motion Systems Ltd.; Oxford, UK) and Vicon Nexus 1.8.5 software. Data were transported into R custom coding statistical analysis software (version 3.5.2; The R Foundation) to calculate velocity analyses which determined mean and peak concentric (MCV, PCV) and eccentric (MEV, PEV) values. Participants were grouped by their relative strength (body mass/1RM) in the back squat, as well as their ability to move often prescribed loads with greater speed (63-70%1RM, 83-87%1RM). Between-groups comparisons were made for MCV at all loading conditions, and correlational relationships between all velocity measures (MEV, PEV, MCV, PCV) were examined for each group. For all subjects, there was a significant effect for relative intensity (%1RM) on MCV, but only for the groups organized by MCV at 63-70%1RM and 83-87%1RM was there a between-subjects effect for group. Correlational analyses between velocity measurements during concentric and eccentric phase of the back squat showed a tendency for high relationships (r = 0.5-0.69) between all phases that weakened as the relative intensity increased. These differences were illustrated uniquely between subject grouping conditions. These results indicate that load-velocity characteristics of the back squat cannot necessarily be positively related to strength level in the movement, and that profiling athletes by their velocities at specific relative intensities could be an effective means of organization.

International Telemetering Conference Proceedings / October 26-29, 1992 / Town and Country Hotel and Convention Center, San Diego, California / A fiber optic event timing system was developed for the High Speed Test Track at Holloman Air Force Base, Alamogordo, NM. The system uses fiber optic sensors to detect the passage of rocket sleds by different stations along the track. The sensors are connected by fiber optic cables to an electronics package that records the event time to a resolution of 100 nanoseconds. By use of a GPS receiver as the timebase, the event time is stored to an absolute accuracy of 300 nanoseconds. Custom VMEbus boards were developed for the event timing function, and these boards are controlled by a programmable high speed sequencer, which allows for complicated control functions. Each board has 4 electro-optic channels, and multiple boards can be used in a VMEbus card cage controlled by a single board computer. The system has been tested in a series of missions at the Test Track.

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