بررسي تجربي و عددي اثر زاويه و شكل موج ساز بر ميدان جريان و پروفيل موج پايين دست

چكيده انگليسي :

Experimental and Numerical Study of the Effect of Wave Maker Shape and Angle on Flow Field and Downstream Wave Profile Morteza Naghmekou m naghmekou@me iut ac ir Date of Submission 2017 01 15 Department of Mechanical Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language Farsi Supervisors Mohammad Reza Tavakolinezhad Mahdi Nili Ahmadabadi mrtavak@cc iut ac ir m nili@cc iut ac ir Abstract Study about wave and relative phenomena is important among researchers This study investigates ex perimentally and numerically the effect of shape and angle of a piston wave maker paddle on velocity field and downstream wave profile In experimental section white light technique for evaluating wave profile and PIV technique to measure the velocity field and particle velocity profiles has been used In numerical solution Navier Stokes equations in two dimensions have been solved by Fluent software In this study the boundary layer is about 3cm and can be ignored At first one condition is selected that have good compli ance with solitary wave This condition has been surveyed experimental and numerical and validated with available theory formula about solitary wave The experimental and numerical velocity profiles of particles under wave tip have very good compliance to each other and have about 7 percent error with theory The effect of paddle s angle and mean speed on downstream flow was investigated In experimental section paddle s angles have 0 15 and 30 degree from vertical position and in numerical section this angle is set 0 5 10 15 20 25 and 30 degree Wave paddle mean speed was set as 0 341 0 38 and 0 43 m s in both experi mental and numerical studies The motion of wave paddle in numerical solution exported from experimental tests and applied to boundary condition Uncertainty of experimental test in white light technique and PIV technique was measured and was about 2 and 3 percent respectively Wave height and tip velocity has not been obvious affected by wave paddle s angle but they increased almost linear by increasing wave paddle s mean speed In addition velocity profile of particles under wave tip was investigated By increasing wave paddle s mean speed in low paddle s angle this profile is increased but in larger angles there are no changes By changing in wave paddle s angle in constant mean speed there is no obvious change in the velocity pro file Velocity vector in numerical and experimental investigation shows a pattern similar to shallow water solitary wave because vortex size near to wave surface is same as channel floor and this is the property of shallow water waves By calculating horizontal force per width unit on wave paddle in numerical solution in first second of paddle motion paddle s angle 20 degree have minimum horizontal force on paddle and has been selected for evaluating arc shapes for shape of wave paddle In this angle eight shape selected as paddle four arc with two concavities All of them are arc with angles 15 30 45 and 60 and two concavities toward beginning and end of wave channel In constant arc angle the shape that have concavity toward beginning of wave channel have less horizontal force on it Best shape for paddle in 20 degree is 15 degree arc that its concavity is toward beginning of wave channel Key Words Wave maker effect Ship side profile optimization solitary wave wave generation Shal low water

نقمه كو، مرتضي

بررسي تجربي و عددي اثر زاويه و شكل موج ساز بر ميدان جريان و پروفيل موج پايين دست

توليد موج , بهينه سازي زاويه كشتي , تك موج , امواج سطحي , آب كم عمق