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Neste trabalho, o método de volumes finitos foi utilizado com esquema de discretização mais elaborado, chamado Flux-Spline, a fim de simular numericamente problemas unidimensionais não lineares de infiltração de água em solo hidraulicamente homogêneo não-saturado. Problemas-teste foram apresentados e resolvidos para alguns valores e combinações dos dois parâmetros adimensionais de governo, para demonstrar as vantagens do novo esquema quando comparado ao tradicional esquema de diferença central. Os resultados obtidos mostraram melhor desempenho do esquema quando comparado à diferença central, em todos os casos simulados, demonstrando que o esquema pode ser recomendado para a simulação numérica de movimentação de água em solo hidraulicamente homogêneo não-saturado.In this work the finite volume method was used with an improved scheme of discretization called Flux-Spline, for the numerical study of non-linear problems in uni-dimensional water flow in hydraulically homogeneous unsaturated soil. Test-problems were presented and resolved to some values and combinations of the two governing non-dimensional parameters to demonstrate the advantages of the new scheme when compared to the traditional central difference scheme. The results obtained showed a better performance of the new scheme when compared to the central difference scheme in all simulated cases, demonstrating that the scheme can be recommended for numerical simulation of water movement in hydraulically homogeneous unsatured soil.

Water movement in saturated soil will affect runoff and infiltration in an area, while water movement in soil processes influenced by soil physical properties. Changes in land use affect the soil physical properties. Changes in land use and differences in the nature of land which includes land use previously existing vegetation into land that does not exist or lack of vegetation resulted in infiltration and percolation rate be changed on the ground and allow the process of infiltration of large, causing the decrease in recharge areas direct rainwater and decrease the availability of ground water. Measurement of water movement in saturated soil conditions or soil Saturated Hydraulic Conductivity (SHC) is very important because SHC role in determining water runoff, infiltration and percolation. The research aimed to know the value of saturated hydraulic conductivity of soil in different land use by using the constant head method and the physical properties of soil including soil texture, weight, density, and porosity in the five land use on three different soil depths. Research conducted in the area Sumbersari in December 2008 until October 2009. Research effect of soil physical properties on using constant head method on five land use is residential population (T1), field (T2), garden tomatoes (T3), shrubs (T4), irrigated rice field (T5) at three different depths ie 0-15 cm (K1), 15-30 cm (K2), and 30-45 cm (K3). The physical properties of soil analyzed include soil texture, weight, density, porosity, and soil moisture content. Results showed that the highest SHC value at all points of location is the location of irrigated rice fields with a depth of 30-45 cm. The main factor affecting the value of SHC is the weight value. Soil physical properties that influence the value of SHC is the soil texture and soil porosity. The results SHC recommended as a reference for land use conditions and other locations with similar soil physical properties.ABSTRAKPergerakan air dalam tanah jenuh akan mempengaruhi limpasan dan infiltrasi pada suatu daerah, sedangkan proses pergerakan air dalam tanah dipengaruhi oleh sifat-sifat fisik tanah. Perubahan penggunaan lahan sangat mempengaruhi sifat-sifat fisik tanah. Perubahan penggunaan lahan dan perbedaan sifat – sifat dasar tanah yang meliputi alih fungsi lahan yang semula ada vegetasi menjadi lahan yang tak ada atau minim vegetasi mengakibatkan laju infiltrasi dan perkolasi pada tanah menjadi berubah dan memungkinkan terjadinya proses infiltrasi yang cukup besar, menyebabkan semakin berkurangnya daerah resapan air hujan secara langsung dan penurunan ketersediaan air tanah. Pengukuran pergerakan air dalam tanah kondisi jenuh atau Konduktivitas Hidrolik Jenuh tanah (KHJ) sangat penting karena KHJ berperan dalam penentuan limpasan air, infiltrasi, dan perkolasi. Penelitian bertujuan untuk mengetahui besarnya nilai konduktivitas hidrolik jenuh tanah di berbagai penggunaan lahan dengan menggunakan metode constant head dan sifat fisik tanah meliputi tekstur tanah, berat isi, berat jenis, dan porositas di 5 penggunaan lahan pada 3 kedalaman tanah yang berbeda. Penelitian dilaksanakan di area Kelurahan Sumbersari pada bulan Desember 2008 hingga bulan Oktober 2009. Penelitian pengaruh sifat fisik tanah terhadap KHJ dengan menggunakan metode constant head pada 5 penggunaan lahan yaitu pemukiman penduduk (T1), lapangan (T2), kebun tomat (T3), semak belukar (T4), sawah irigasi (T5) pada 3 kedalaman yang berbeda yaitu 0-15 cm (K1), 15-30 cm (K2), dan 30-45 cm (K3). Sifat fisik tanah yang dianalisis antara lain tekstur tanah, berat isi, berat jenis, porositas, dan kadar air tanah. Hasil penelitian menunjukkan bahwa nilai KHJ tertinggi pada seluruh titik lokasi adalah lokasi sawah irigasi dengan kedalaman 30-45 cm. Faktor utama yang mempengaruhi nilai KHJ adalah nilai berat isi. Sifat-sifat fisik tanah yang mempengaruhi nilai KHJ adalah tekstur tanah dan porositas tanah. Hasil penelitian direkomendasikan sebagai acuan KHJ penggunaan lahan lokasi lain dengan kondisi dan sifat fisik tanah yang sama.

Submitted by Severina Oliveira (severina.sueli@ufcg.edu.br) on 2019-02-20T18:47:27Z No. of bitstreams: 1 CELSEMY ELEUTÉRIO MAIA-TESE-PPGRN 2005.pdf: 3640655 bytes, checksum: 1705d44a1d60017c7a9962e3104eeba9 (MD5) Made available in DSpace on 2019-02-20T18:47:27Z (GMT). No. of bitstreams: 1 CELSEMY ELEUTÉRIO MAIA-TESE-PPGRN 2005.pdf: 3640655 bytes, checksum: 1705d44a1d60017c7a9962e3104eeba9 (MD5) Previous issue date: 2005-04-11 CNPq Informações da geometria do bulbo molhado são importantes para o dimensionamento e manejo da irrigação localizada, principalmente para estimar o volume de solo molhado, a vazão do emissor e o tempo de aplicação de água. O objetivo deste estudo foi avaliar modelos matemáticos para o efeito da combinação entre tempo de aplicação de água e vazão do emissor nas dimensões e volume molhado do solo sob irrigação localizada superficial. O estudo foi realizado no agropólo Assu-Mossoró, Rio Grande do Norte, em seis solos classificados como Luvissolo Crômico, Argissolo Vermelho Amarelo, Cambissolo Háplico, Neossolo Quartzarênico, Latossolo Vermelho e Neossolo Flúvico. Os tratamentos foram compostos de quatro tempos de irrigação (1, 2, 4 e 7 h) e quatro vazões dos emissores (1, 2, 4 e 8 L h-1), dispostos em delineamento experimental em blocos inteiramente casualizados no esquema de parcelas subdivididas, com três repetições, tendo o tempo (t) como parcela e a vazão (q) com subparcela. Após a aplicação do volume de água foram abertas trincheiras e medidas as dimensões do diâmetro superficial (Ds), diâmetro máximo (Dmax), profundidade máxima (Zmax) e profundidade onde ocorre o diâmetro máximo (ZDmax). Foram avaliados modelos matemáticos para estimar as dimensões e volume do bulbo molhado, cuja comparação foi realizada pelo quadrado médio dos desvios (MSD). Observou-se que o modelo potencial e de superfície de resposta estimam satisfatoriamente as dimensões do bulbo molhado em função de q e t; a relação Dmax/Zmax1/3 foi melhor ajustada pelo modelo superfície de resposta que Dmax/Zmax em função de q e t, existe relação linear positiva entre o diâmetro superficial (Ds) e as dimensões do bulbo molhado. Modelos semi-empíricos foram propostos para estimativa do diâmetro máximo e os valores estimados se ajustaram bem aos observados. Os modelos propostos para estimativa do volume molhado estimaram satisfatoriamente o volume do bulbo. Information on the geometry of wetted soil volume under trickle irrigation is important for the design and operation of these irrigation systems, and also for the management of irrigation as a function of emitter discharge and wetted volume. This research was carried out in the state of Rio Grande do Norte, Brazil, to study the effect of different combinations of emitter discharge and time of water application on the dimension and volume of wetting in six soils (Entisol, Ultisol, Inceptisol, Psamment, Oxisol, Fluvent). The factors time of water application (t = 1, 2, 4 and 7 h) and discharge rate (q = 1, 2, 4 and 8 L h-1) were studied in a split split-plot design with three replications. Trenches were open after application of the different water volumes and the following measures were taken: depth (Zmax), diameter at soil surface (Ds), maximum width (Dmax), and depth of maximum width (ZDmax). Models proposed were evaluated by Mean Squared Deviation (MSD) between predicted and measured values. Empiric equations for Dmax (q, t), Zmax (q, t), Ds (q, t) and ZDmax (q, t) adjusted well to power and surface response models. Values of the semi-empiric models proposed for maximum width had good agreement with field observed values. Models proposed also predicted wetted soil volume.

Neste trabalho, o método de volumes finitos foi utilizado com esquema de discretização mais elaborado, chamado Flux-Spline, a fim de simular numericamente problemas unidimensionais não lineares de infiltração de água em solo hidraulicamente homogêneo não-saturado. Problemas-teste foram apresentados e resolvidos para alguns valores e combinações dos dois parâmetros adimensionais de governo, para demonstrar as vantagens do novo esquema quando comparado ao tradicional esquema de diferença central. Os resultados obtidos mostraram melhor desempenho do esquema quando comparado à diferença central, em todos os casos simulados, demonstrando que o esquema pode ser recomendado para a simulação numérica de movimentação de água em solo hidraulicamente homogêneo não-saturado. In this work the finite volume method was used with an improved scheme of discretization called Flux-Spline, for the numerical study of non-linear problems in uni-dimensional water flow in hydraulically homogeneous unsaturated soil. Test-problems were presented and resolved to some values and combinations of the two governing non-dimensional parameters to demonstrate the advantages of the new scheme when compared to the traditional central difference scheme. The results obtained showed a better performance of the new scheme when compared to the central difference scheme in all simulated cases, demonstrating that the scheme can be recommended for numerical simulation of water movement in hydraulically homogeneous unsatured soil.