Inflow

About: Inflow is a research topic. Over the lifetime, 9752 publications have been published within this topic receiving 105378 citations.

A computational study of 3D flow structure in two consecutive bends subject to the influence of tributary inflow in the middle Yangtze River

Abstract: Enhanced understanding of turbulent flow structure in bends in natural rivers is essential for waterway regulation, navigation safety and environmental and ecological wellbeing. However, the flow structure in consecutive bends has so far remained poorly understood, especially when it is subject to the influence of tributary inflow. Here, the 3D flow structure in two consecutive bends, namely Qigongling (upstream bend) and Guanyinzhou (downstream bend), subject to the influence of tributary inflow from the Dongting Lake, in the middle Yangtze River, is numerically investigated. The RNG k-ϵ turbulence model is applied under the FLOW-3D software platform. The results show that: (1) the high-velocity zones shift from inner to outer banks in both consecutive bends. (2) No secondary current cells are spotted at the entrance of either bend. At the bend apex, multiple cells of secondary currents appear in Qigongling, but not in Guanyinzhou under certain discharges. (3) Recirculation vortices occur mainly on the inner bank (small-scale) in Qigongling, but on both the inner (small-scale) and outer (large-scale) banks in Guanyinzhou. (4) With increasing mainstem (tributary) discharge, the velocity and turbulent kinetic energy enlarge (reduce). However, a decrease of the secondary current strength in Qigongling and an increase in Guanyinzhou (all increase in both bends).

Effect of fines content on shear deformation properties of sand subjected to pore water inflow after undrained cyclic shearing

Abstract: 緩傾斜地盤において地震後に時間遅れを伴う流動変形が生じる要因の一つとして，加振により上昇した過剰間隙水圧が再配分される過程で，表層の難透水層直下の砂層に下層から流入する間隙水の存在が挙げられる．間隙水流入により体積膨張を伴いながらせん断変形が進展するきれいな砂の挙動は実験的に調べられているものの，細粒分の影響に着目した研究はほとんど行われていない．本研究では，細粒分含有率（Fc = 0, 10, 20, 30%）を変化させた供試体を作製し，中空ねじり試験機を用いて初期せん断応力を載荷した上で非排水繰返しせん断履歴を与えた後，間隙水注入による強制膨張せん断試験を実施した．その結果，細粒分含有率は，砂の非排水繰返しせん断特性のみならず，その後の間隙水流入時のダイレイタンシー特性にも影響を及ぼすことが明らかとなった．

Transition of separated flow over a bump under unsteady inflow conditions

Abstract: Laminar flow separation is a ubiquitous phenomenon present in several aeronautical applications, such as low-pressure turbines (LPT) and Micro Aerial Vehicle wings. Flow separation is associated with detrimental effects on aerodynamics and performance. These effects are related to the size and dynamics of the separated flow, which in turn are dominated by the laminar-turbulent transition process. While transition in separated flows and the underlying hydrodynamic instabilities are relatively well known for steady flow conditions [1,2,3], the impact of temporal variations on the incoming flow has received less attention [4]. In this work, we study the qualitative and quantitative changes on the separated flow dynamics on account of unsteady changes in the inflow conditions.

Thrust Vector Observation for Force Feedback-Controlled UAVs

Abstract: This paper presents a novel approach to Thrust Vector Control (TVC) for small Unmanned Aerial Vehicles (UAVs). The difficulties associated with conventional feed-forward TVC are outlined, and a practical solution to conquer these challenges is derived. The solution relies on observing boom deformations that are created by different thrust vector directions and high-velocity air inflow. The paper describes the required measurement electronics as well as the implementation of a dedicated testbed that allows the evaluation of mid-flight force measurements. Wind-tunnel tests show that the presented method for active thrust vector determination is able to quantify the disturbances due to the incoming air flow.