Process experience of waving measurements for engineering survey Печать

KOROTKOV S.V., ASHIHMIN V.A.
Open Society " AMIGE ", Russia

Waves are one of elements of dynamics of the waters limiting safe work of chisel complexes of various types.

The primary goal of measurements of waves in engineering researches - reception of quantitative estimations of key parameters of excitement (height, the period, length), is especial in storm conditions, on concrete sites of the sea water areas intended for construction. Also the data of measurements of waves are necessary for adjustment (verification) of the wave models used for calculations of parameters of waves of small security.

The oceanographic database of Open Society "AMIGE" contains significant volume of measurements of the excitement received the last years with the help string wave recorders, established on drilling platforms. Advantages of such records - long, covering different seasons, numbers of measurements directly fluctuations of a free surface exhausting. Lacks - a conclusion of the data to the paper carrier, different step-type behavior and scales of record, etc.

Now measurements of waves by employees of Open Society "AMIGE" are carried out with use of two types of devices: acoustic Doppler measuring device ADCPWH600 companies RD Instruments (USA) and SBE-26 (SBE 26plus) companies SEA-BIRD ELECTRONIC, INC (USA). Last two devices make measurements of waves indirectly on changes of pressure of a water column above the device.

In the report the questions connected to planning of measurements and data processing of recorders SBE are considered.

Recorders SBE are widely widespread measuring devices of waves and tides. Last updating of the device allow the user to establish independently a mode of measurements, the opportunity of " the postponed start " has appeared, the volume of internal memory has increased, maintenance has improved program.

Lack of the device consists in the principle of measurement of waves on pressure of the water, shown in distortion of characteristics of excitement in shallow areas of carrying out of researches during storm cycles, that is then when results of measurements are the most valuable.
The software of the device does not allow to carry out any edition of the received data. Target parameters of excitement in engineering units are significant heights and the periods of waves in a time number.

In Open Society "AMIGE" during operating experience of recorders SBE the program complex has been developed, allowing to allocate and edit separate wave record, to carry out their statistical processing with visualization of results of calculations and to form time numbers of heights and the periods of waves of various probability in system (a number of the consecutive waves having one origin).

Strong variability of excitement in shallow areas from wind conditions results in necessity of more often measurement of excitement, in comparison with deep-water areas of the seas. Consequence of it is the repeated increase in volume of measurements and, in case of the storm conditions deformed wave records which demand careful updating.

Such updating uses two approaches. The first consists in sequence of calculations with various factors of easing (attenuation) of excitement. Calculation of base factor is made during scheduling the device before its installation on of-line buoy-based station and remains to constants during all work of the device on of-line buoy-based station.

In the storm periods, in connection with change of height of a water column above the device and waves collapse, incorrect work of constant value of this factor is shown.

Final values of parameters of excitement get out on ratio of average and maximal heights of waves in wave records and according to the general course of time variability of parameters of waves in conformity with wind conditions and morph metrical features of area of researches.
Updating wave records with check of ordinates of measurements allows to remove the false fine waves determined by the device formally but which deform the final statistical data a little.

Such approach now demands laborious work and the big expenses of time that is not always possible at the reduced terms of preparation of accounting materials.

The second approach consists in aprioristic representation is unreal high waves emissions, and application to such data of various methods of checks of time numbers on discharge.

As such method Lennon's method [Lennon G.W., 1965] with the subsequent visual comparisons of the initial and settlement data and check of distribution of the last on the set intervals of heights of waves was used.
The final control, as well as over the first case, was carried out on the general course of time variability of parameters of waves and parities between their average and maximal heights.

Such approach does not allow editing height of weak waves, but considerably simplifies procedure of mass processing wave records and reduces terms of such processing.

The literature
Lennon G.W. The treatment of hourly elevations of the tide using an ibm 1620 - Int. Hydr. Rev., Vol. XLII, №2, 1965, р.129

OIL AND GAS OF ARCTIC SHELF 2008