HYDRAULIC CALCULATION METHODS  FOR PREDICTION OF  MAXIMAL DEPTHS OF LOCAL WASH-OUT OF EARTH AND MAXIMAL VALUES OF THE LATERAL WASH-OUT (SLOPES) OF BEDS  BY A POST-JUMP STREAM IN THE DOWNSTREAM POOLS OF HYDRAULIC COMPLEXES

A.GIOSHVILI
(Georgia)

The proposed methods are applied to determine 1) time changes of a maximal depth of the pit of local wash-out Yr and its limiting value Yrm  behind the horizontal water apron or the rear apron in the conditions of bed regime of the conjugation of  pools in he case of a hydraulic jump occurring within the limits of the  water apron; 2) the time corresponding to the intermediate   and stabilized t1 configuration of the local wash-out pit; 3) a maximal lateral wash-out of the bed l  in the downstream pool behind the water apron and the rear apron, i.e. in the local wash-out pit  and as well as downstream, with still noticeable wave oscillations of the surface produced by the transformation of waves generated by a hydraulic jump; 4) an average value of the discharge of drift QSL washed away from the slopes by a longitudinal wave flow; 5) the volume of the ground WS washed away from the slopes during the time t, its maximal value WSm and the time t2 of stabilization of the slopes washed-out by waves.

The application area of the methods, the main restrictions, the notation used and a list of initial data needed for prediction calculation are discussed.




METHOD OF FORECASTING THE DYNAMIC STABILITY OF COAST (BEACH)

A.GIOSHVILI
(Georgia)

The formula is derived for determining the wash-out instability of the coastline (beach) by means of the width l of a sea, lake, water reservoir and so on.

For the case of beach wash-out by storm waves the formula makes it possible to determine the beach width l using the values of wave amplitudes ã and drift particles of average diameter d = d95%.

The slope value i0 is determined for the dynamically stable beach formed on the coast line as a result of the repeated  action of waves (at the time of wash-out process termination). For the coastline wash-out by waves with amplitude  ã , relations are obtained for determining the width of the surface part of the beach for three (i = i0; i < i0 and i > i0) initial value of the slope i of the underwater part of the beach.




COMPUTER MODELING OF LAMINAR FLOW OF CIRCLES AND ARCS SUBMERGED IN FLUID

D.KIGURADZE, K.GIGITELASHVILI, O.KIGURADZE
(Georgia)

For simulation of fluid or gas, program package including FLUENT and GAMBIT is used.

Various shapes of forms submerged in fluid: circle, 3/4, ½ and 1/4 arcs of circles, flow computer images are presented on graphics I, II, III and IV. Average value of Reynolds numbers is equal to  , and flow velocity 1-4.7 mm/s. There is seen couple of whirlpool per circle flow, center-to-center distance of which is in correlation with data received by experiments (semi-circle flow). At laminar flow, flow reverse of circles and its various arcs, practically have no effect on hydrodynamic picture of flow.

Firstly, visual imagination of hydrodynamic processes is important for studying purposes. Visual images and animated pictures significantly raise understanding of theoretical skills at lectures and workshops. Supporting of formation of hydrodynamic intuition in attendees is also key factor.