scholarly journals MATHEMATICAL SIMULATION OF BOTTOM SEDIMENT MOTION BY WAVES

1966 ◽  
Vol 1 (10) ◽  
pp. 43 ◽  
Author(s):  
J.W. Kamphuis
Keyword(s):  
Mathematical Model ◽  
Bottom Sediment ◽  
Mathematical Simulation ◽  
Wave Action ◽  
Field Conditions ◽  
Uniform Size ◽  
Actual Field ◽  
Horizontal Bottom

A mathematical model is developed to calculate the amount of bottom sediment moved by wave action. The simplified case of a horizontal bottom and spherical material of uniform size is presented here; however, with some further groundwork it is thought that the model may be extended to actual field conditions without too much difficulty.

Some characteristics of the germination of Queensland blue grass on cracking black earths

1978 ◽  
Vol 29 (6) ◽  
pp. 1147 ◽  
Author(s):  
LA Watt
Keyword(s):  
Water Availability ◽  
Field Conditions ◽  
Adaptive Mechanism ◽  
Surface Layers ◽  
Large Numbers ◽  
Actual Field ◽  
Germinated Seeds

An intermediate stationary stage in the germination of Queensland blue grass (Dicanthium sericeum L.) caused by limiting water availability was examined. It was found that partially germinated seed can maintain viability over extended periods of desiccation and that large numbers of these partially germinated seeds are found under simulated and actual field conditions. Results indicate that this phenomenon is an adaptive mechanism which assists establishment on black cracking earths in which rapid drying of surface layers is characteristic.

Effect of Water Table Depth on the Yield of Seven Sugarcane Varieties in Puerto Rico

1969 ◽  
Vol 60 (2) ◽  
pp. 228-237
Author(s):  
Raúl Pérez Escolar ◽  
William F. Allison
Keyword(s):  
Puerto Rico ◽  
Water Table ◽  
Commercial Production ◽  
Water Table Depth ◽  
Field Conditions ◽  
Sugarcane Varieties ◽  
Effect Of Water ◽  
Actual Field ◽  
Response To Water

The effect of water table depth on yield of sugarcane varieties PR 980, PR 1028, PR 1059, PR 1141, PR 64-610, PR 61-632 and PR 64-2705 was studied in lysimeter tanks in the field. Using plastic drains at varying distances and depths, variety PR 980 was studied on a 5-ha farm. Results obtained show that varieties differ in their response to water table conditions. Varieties PR 980, PR 1059, PR 64-610, PR 61-632 and PR 64-2705 yielded significantly more cane and sugar when the water table was lowered. Varieties PR 1028 and PR 1141 did not show statistically significant differences among treatment differentials. Under actual field conditions, using perforated plastic drains, variety PR 980 yielded significantly more sugar than in undrained plots. The results obtained in the lysimeter tanks are in accord with those observed under commercial production.

Mathematical model of the temperature field around a borehole with radioactive wastes and its experimental verification in field conditions

1985 ◽  
Vol 59 (6) ◽  
pp. 994-998
Author(s):  
E. G. Drozhko ◽  
V. I. Karpov ◽  
A. S. Stepanov ◽  
I. I. Kryukov ◽  
V. F. Savel'ev ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Temperature Field ◽  
Experimental Verification ◽  
Radioactive Wastes ◽  
Field Conditions

Mathematical Simulation of Hydraulic Power Pulse Machine at Matlab

2016 ◽  
Vol 685 ◽  
pp. 240-243 ◽  
Author(s):  
M.V. Novoseltseva ◽  
E.N. Pashkov ◽  
I.A. Masson
Keyword(s):  
Mathematical Model ◽  
Mathematical Simulation ◽  
Model Simulation ◽  
General Idea ◽  
Restriction Factors ◽  
Hydraulic Power ◽  
Power Pulse ◽  
Machine Operation ◽  
Simulation Results

General idea of mathematical simulation is set. Equations that describe hydraulic power pulse machine operation are described. Restriction factors are identified; they are included in mathematical model simulation. Mathematical simulation results are shown for essential parts of machine. Results of hydraulic power pulse machine mathematical simulation are presented.

The transfer of fluorine in the soil–wheat system and the principal source of fluorine in wheat under actual field conditions

2012 ◽  
Vol 137 ◽  
pp. 163-169 ◽  
Author(s):  
Cheng Wang ◽  
Zhongfang Yang ◽  
Lingxiao Chen ◽  
Xuyin Yuan ◽  
Qilin Liao ◽  
...  
Keyword(s):  
Field Conditions ◽  
Principal Source ◽  
Actual Field ◽  
Soil Wheat

Selenium supplementation of Portuguese wheat cultivars through foliar treatment in actual field conditions

2012 ◽  
Vol 297 (2) ◽  
pp. 227-231 ◽  
Author(s):  
Catarina Galinha ◽  
Maria do Carmo Freitas ◽  
Adriano M. G. Pacheco ◽  
José Coutinho ◽  
Benvindo Maçãs ◽  
...  
Keyword(s):  
Selenium Supplementation ◽  
Field Conditions ◽  
Wheat Cultivars ◽  
Foliar Treatment ◽  
Actual Field

scholarly journals Mathematical simulation of hard excitation of cavitation self-oscillations in a liquid-propellant rocket engine feed system

2021 ◽  
Vol 2021 (1) ◽  
pp. 29-36
Author(s):  
S.I. Dolgopolov ◽  
Keyword(s):  
Mathematical Model ◽  
Mathematical Simulation ◽  
Small Amplitude ◽  
External Disturbance ◽  
Liquid Propellant ◽  
Feed System ◽  
Hard Excitation ◽  
Set Up ◽  
Pump Inlet ◽  
Propellant Rocket

Hard self-oscillation excitation differs from soft excitation in that self-oscillations are set up only if the initial departure of an oscillating system from equilibrium is strong enough. Experimental studies of cavitation oscillations in hydraulic systems with cavitating pumps of liquid-propellant rocket engines ((LPREs) include works that describe hard excitation of cavitation oscillations. By mow, hard excitation regimes have not been explained theoretically, to let alone their mathematical simulation. This paper presents a mathematical model of hard excitation of cavitation oscillations in a LPRE feed system, which comprises a mathematical model of cavitation self-oscillations in a LPRE feed system that accounts for pump choking and an external disturbance model. A mechanism of hard excitation of cavitation oscillations in a LPRE feed system is proposed. It is well known that hard excitation of cavitation self-oscillations may take place in cases where the pump feed system is near the boundary of the cavitation self-oscillation region. In this case, the self-oscillation amplitudes are small, and they are limited only by one nonlinearity (cavity volume vs. pump inlet pressure and flow relationship). Under excitation of sufficient intensity, the pump inlet pressure and flow find themselves in the choking characteristic; this may be responsible for choking and developed cavitation self-oscillations, which remain of interrupted type and do not go into the initial small-amplitude oscillations even after excitation removal. A mathematical simulation of hard excitation of cavitation self-oscillations was conducted to determine the parameters of cavitation self-oscillations in a bench feed system of a test pump. The simulation results show that without an external disturbance the pump system exhibits small-amplitude self-oscillations. On an external disturbance, developed (interrupted) cavitation oscillations are set up in the system, which is in agreement with experimental data. The proposed mathematical model of hard excitation of cavitation self-oscillations in a LPRE feed system allows one to simulate a case observed in an experiment in which it was possible to eliminate cavitation self-oscillations by an external disturbance.

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