Influence of unsteady flow and sediment size on scour processes at box culvert outlets using turbulence models
Environment and Water Engineering, cilt.12, sa.1, ss.177-193, 2026 (Scopus)
- Yayın Türü: Makale / Tam Makale
- Cilt numarası: 12 Sayı: 1
- Basım Tarihi: 2026
- Doi Numarası: 10.22034/ewe.2026.584704.2100
- Dergi Adı: Environment and Water Engineering
- Derginin Tarandığı İndeksler: Scopus
- Sayfa Sayıları: ss.177-193
- Anahtar Kelimeler: Box Culvert, Flow Rate, k-ε, LES, Sediment Size
- Van Yüzüncü Yıl Üniversitesi Adresli: Evet
Özet
This study evaluates the performance of two commonly used turbulence models, the standard k–epsilon (k–ε) model and the Large Eddy Simulation (LES) approach, in predicting scour processes downstream of a box culvert under unsteady flow conditions. The numerical results are compared with experimental observations and previously validated simulations obtained using the Renormalization Group (RNG) turbulence model. Numerical simulations were performed using unsteady hydrographs with varying discharge rates and two sediment–hydrograph scenarios involving d₅₀= 0.85 mm and 2 mm to investigate the effects of these conditions on scour behavior. Model performance was quantitatively assessed using statistical indicators, including the correlation coefficient (R), Mean Absolute Error (MAE), Root Mean Square Error (RMSE), and Mean Absolute Percentage Error (MAPE). The results indicate that the maximum scour depth increases during the rising limb of the hydrograph and then stabilizes or partially recovers during the falling limb for both sediment sizes. The RNG model showed the best overall agreement for d₅₀= 0.85mm and remained competitive for d₅₀= 2mm. LES more accurately captured the downstream migration of the maximum scour location in coarser sediment, whereas the standard k–ε model generally overpredicted scour depth, confirming that prediction accuracy depends on the selected turbulence model and sediment characteristics.