scholarly journals Experimental and Numerical Determination of the Head Loss of a Pressure Driven Flow through an Unlined Rock-Blasted Tunnel

Water ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 3492
Author(s):  
Jochen Aberle ◽  
Pierre-Yves Henry ◽  
Fabian Kleischmann ◽  
Christy Ushanth Navaratnam ◽  
Mari Vold ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Numerical Model ◽  
Numerical Simulations ◽  
Stokes Equations ◽  
Hybrid Approach ◽  
Remote Sensing Data ◽  
Head Loss ◽  
Scale Model ◽  
Sensing Data

The friction loss in a part of the rock-blasted unlined tunnel of the Litjfossen hydropower plant in Norway was determined from experimental and numerical studies. Remote sensing data from the prototype tunnel provided the input data for both the numerical model and the construction of a 1:15 scale model with an innovative milling approach. The numerical simulations were based on the solution of the Reynolds-averaged Navier–Stokes equations using the CFD program OpenFoam. Head loss measurements in the scale model were carried out by means of pressure measurements for a range of discharges and were compared against the results of the numerical model. The measured data were used to determine the Darcy–Weisbach and Manning friction factors of the investigated tunnel reach. The high-resolution remote sensing data were also used to test the applicability of existing approaches to determine the friction factor in unlined rock blasted tunnels. The results of the study show the usefulness of the chosen hybrid approach of experimental investigations and numerical simulations and that existing approaches for the determination of head losses in unlined tunnels need to be further refined.

Tsunami Assessment and Evacuation Analysis Using Remote Sensing for Tianya District of Sanya City, China

2019 ◽  
Vol 13 (05n06) ◽  
pp. 1941003
Author(s):  
Jingming Hou ◽  
Zhiyuan Ren ◽  
Peitao Wang ◽  
Juncheng Wang ◽  
Yi Gao
Keyword(s):  
Remote Sensing ◽  
Numerical Model ◽  
Infrared Imaging ◽  
Remote Sensing Data ◽  
Tsunami Inundation ◽  
Sensing Data ◽  
Inundation Area ◽  
Nighttime Lights ◽  
Elevation Data ◽  
Landsat Satellite

Tsunami is one of the world’s most dangerous marine disaster. In this paper, freely available remote sensing data are applied to study the hazard, vulnerability, and evacuation in the event that a tsunami strikes the district of Tianya in the city of Sanya. Tsunami inundation is calculated using a tsunami numerical model, and the tsunami vulnerability and evacuation in the inundation area are analyzed. Aster Global Digital Elevation Model elevation data are applied to provide input data for the tsunami numerical model and thus obtain tsunami inundation areas, while they are also used to study the surface slope for evacuation. Landsat satellite imagery is used to analyze land–water borders and land cover in both hazard assessment and evacuation analysis. Visible Infrared Imaging Radiometer Suite nighttime lights data provide information of the socioeconomic activity for vulnerability analysis. The analysis results show that the remote sensing data is suitable for tsunami assessment and evacuation analysis of China’s county-level region. We can get a general understanding about tsunami vulnerability and evacuation situation. One kind of remote sensing data can accomplish several tasks, avoiding the error caused by different source data. Remote sensing can play an important role in tsunami assessment.

scholarly journals Determination of the Pyro-Factor Ecological Successions Duration in the Zonal Landscapes of the Volgograd Region According to the Remote Sensing Data

2020 ◽  
pp. 44-53
Author(s):  
Stanislav Shinkarenko ◽  
◽  
Asel Berdengalieva ◽  
Valeriya Doroshenko ◽  
Kseniya Oleynikova ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Spectral Characteristics ◽  
Remote Sensing Data ◽  
Field Studies ◽  
Spatial Characteristics ◽  
Sensing Data ◽  
Volgograd Region ◽  
Burnt Areas ◽  
Steppe Fires

The aim of the work is to determine the spatial characteristics of the distribution of the burnt areas of natural zonal landscapes of the Volgograd region with different duration of pyro-factor successions, taking into account the frequency of fires. Based on the previously developed thematic geo-information layers of the steppe fires in the region using overlay operations, the duration of post-pyrogenic periods in the municipal districts of the region was determined, taking into account the total number of fires from 1998–2018. The largest areas covered by fire have a succession duration of 2–3 years and 12–14 years at the beginning of 2019, which corresponds to the fires of 2016–2017 and 2005–2007, respectively. Large areas after the fires of 2001–2002 are located in Ilovlinsky, Kletsky, Pallasovsky and Surovikinsky districts. The largest area of land covered by fire in 2004–2006 is located in the Danilovsky, Ilovlinsky, Olkhovsky and Pallas districts. In our opinion, landscapes affected by fire no more than 5–7 years ago are suitable for the analysis of pyrogenic shifts. These territories are located in Frolovsky, Chernyshkovsky, Kotovsky, Ilovlinsky, Pallasovsky, Leninsky, Kamyshinsky, Staropoltavsky districts. The results will serve as the basis for field studies and the analysis of the spectral characteristics of overgrowing burns from remote sensing materials.

scholarly journals Indirect Validation of Ocean Remote Sensing Data via Numerical Model: An Example of Wave Heights from Altimeter

2020 ◽  
Vol 12 (16) ◽  
pp. 2627 ◽  
Author(s):  
Haoyu Jiang
Keyword(s):  
Remote Sensing ◽  
Numerical Model ◽  
Numerical Models ◽  
Remote Sensing Data ◽  
Validation Method ◽  
Wave Hindcast ◽  
Sensing Data ◽  
Data Pair ◽  
Wave Heights ◽  
Ocean Remote Sensing

Using numerical model outputs as a bridge, an indirect validation method for remote sensing data was developed to increase the number of effective collocations between remote sensing data to be validated and reference data. The underlying idea for this method is that the local spatial-temporal variability of specific parameters provided by numerical models can compensate for the representativeness error induced by differences of spatial-temporal locations of the collocated data pair. Using this method, the spatial-temporal window for collocation can be enlarged for a given error tolerance. To test the effectiveness of this indirect validation approach, significant wave height (SWH) data from Envisat were indirectly compared against buoy and Jason-2 SWHs, using the SWH gradient information from a numerical wave hindcast as a bridge. The results indicated that this simple indirect validation method is superior to “direct” validation.

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