A method of suppressing thermal stratification of reservoirs by stimulating water flow oscillation through daily reservoir regulation

Abstract

The present invention belongs to the technical field of lake and reservoir water ecology improvement and restoration, and discloses a method for suppressing thermal stratification of reservoirs by stimulating water flow oscillations through daily regulation and scheduling of reservoirs. The daily regulation and scheduling process of the reservoir causes gravity waves to form in the main stream of the reservoir, and induces high-frequency water flow oscillations in the tributary bay; the water level in the bay has high-frequency fluctuation characteristics through the water flow oscillation process, and the flow velocity of the water body in the bay is intermittently increased or reduced; the water body is intermittently mixed through the periodic high-frequency oscillation process, causing high-frequency fluctuations in water temperature, thereby achieving the effect of suppressing water temperature stratification. The present invention generates water level fluctuations in front of the dam by regulating the downstream flow of the hydropower station, triggering gravity waves in the main stream, and then inducing high-frequency water flow oscillations in the tributary bay. The present invention can effectively improve the density stratification characteristics of deepwater lakes and reservoirs. Compared with the currently commonly used engineering measures such as stratified water intake, water pumping and aeration, the present invention has the advantages of simple operation, easy implementation, and obvious effect.

Description

Technical Field

[0001] The present invention belongs to the technical field of lake and reservoir water ecology improvement and restoration, and in particular relates to a method for utilizing daily reservoir regulation and scheduling to stimulate water flow oscillation and suppress reservoir thermal stratification. Background Art

[0002] At present, the thermodynamic conditions have changed significantly after the river channel was dammed and formed into a reservoir. The occurrence of seasonal thermal stratification is the most basic physical process in lakes and reservoirs. Generally speaking, the water temperature structure of the vertical profile in lakes and reservoirs includes a variable temperature layer, a thermocline and a stagnation layer from top to bottom. The large difference in density between the upper and lower water bodies in the thermocline can hinder the mixing and exchange of substances in the upper and lower water bodies, and have a significant impact on the vertical distribution of dissolved oxygen and nutrients in the water body, further causing water blooms or black and smelly water bodies and other water quality deterioration problems. Therefore, breaking the thermal stratification of lake and reservoir water bodies has become an important way to alleviate and improve ecological and environmental problems such as lake water quality and algal blooms.

[0003] For the ecological and environmental problems such as water hypoxia, water quality deterioration, algal blooms, and low-temperature water discharge under the background of thermal stratification of lakes and reservoirs, engineering measures are currently mainly adopted, such as stratified water intake, water pumping and aeration, and reservoir scheduling. The main purpose is to strengthen the vertical mixing of water bodies, break the water temperature stratification, increase the vertical transfer and replenishment of substances, and alleviate the ecological mitigation problems caused by water temperature stratification. However, at present, these measures cannot change the temperature stratification of large-volume waters in the reservoir area, and cannot improve the ecological environment of large-scale water bodies in the reservoir area. In the past, the ecological scheduling of reservoirs was mostly based on the medium and long water level scheduling process, and did not consider the ecological and environmental benefits of daily regulation.

[0004] Through the above analysis, the problems and defects of the prior art are as follows:

[0005] (1) Existing engineering measures, such as pumping and aeration, are not suitable for large deep-water reservoirs, have poor effects on improving the temperature stratification of large water bodies, and have high engineering costs.

[0006] (2) In the past, reservoir ecological regulation was mostly based on medium- and long-term water level regulation processes, and did not consider or utilize the ecological and environmental benefits of daily regulation. Summary of the invention

[0007] In view of the problems existing in the prior art, the present invention provides a method for suppressing thermal stratification of a reservoir by stimulating water flow oscillation through daily reservoir regulation.

[0008] The present invention is achieved as follows: a method for utilizing daily reservoir regulation and scheduling to stimulate water flow oscillations to suppress thermal stratification of the reservoir. The method for utilizing daily reservoir regulation and scheduling to stimulate water flow oscillations to suppress thermal stratification of the reservoir includes: by adjusting the discharge flow of the hydropower station (suddenly increasing or decreasing), water level fluctuations in front of the dam are generated, gravity waves in the main stream are triggered, and high-frequency water flow oscillation hydrodynamic phenomena are induced in the tributary bay, thereby achieving the effect of suppressing thermal stratification of the reservoir.

[0009] Furthermore, the method of using daily reservoir regulation to stimulate water flow oscillations to suppress thermal stratification of the reservoir also includes: utilizing the generation and transmission mechanism of surface gravity waves, combined with the daily regulation of the reservoir, to stimulate high-frequency water flow oscillations in the tributary bay; during the water flow oscillation process, accompanied by high-frequency water level fluctuations, the closer to the end of the bay, the greater the amplitude of the water level fluctuation, and at the same time, the flow velocity of the water body in the bay is intermittently increased or decreased, forming an intermittent mixing effect, causing high-frequency fluctuations in the water temperature, thereby slowing down the water temperature stratification in the bay.

[0010] Furthermore, the method of using daily reservoir regulation to stimulate water flow oscillation and suppress reservoir thermal stratification includes the following steps:

[0011] Step one: During the daily regulation of the reservoir, a sudden increase or decrease in outflow will first drive the water level fluctuation at the reservoir head. The magnitude of the water level fluctuation is closely related to the change in outflow and the water level in front of the dam. The water level fluctuation in front of the dam then propagates to the upstream of the reservoir in the form of gravity waves. During this period, the amplitude of the gravity waves will continue to change, and the phase will gradually lag. The change in the amplitude of gravity waves is affected by many factors, including bottom friction, terrain changes, and interaction with upstream or tributary water bodies. Among them, bottom friction and tributary action will continuously dissipate wave energy, resulting in a decrease in amplitude; but the narrowing of the upstream terrain will cause the wave energy to converge, thereby increasing the amplitude;

[0012] Step 2: Under the influence of the gravity wave of the mainstream, the periodic increase or decrease of the water level at the estuary of the tributary will cause the mainstream water body to periodically enter or flow out of the reservoir bay. Taking the rise of the mainstream water level as an example, the mainstream water body enters the tributary reservoir bay and flows upstream. Under the influence of the narrowing of the upstream river channel, the water level along the way gradually rises, the flow rate gradually decreases, and the kinetic energy of the water body gradually converts into potential energy. Subsequently, the potential energy is converted into kinetic energy, the water level gradually decreases, the flow rate first increases and then decreases, and the water body gradually flows out of the reservoir bay. Then it is reflected back at the tributary estuary, forming a periodic reciprocating motion. Similarly, the process of the gravity wave water level reduction at the estuary will also cause the same reciprocating motion of the tributary reservoir bay. However, since the tributary estuary is connected to the mainstream, affected by the large volume of water in the mainstream, the change of the estuary water level can be basically ignored, and the closer the tributary reservoir bay is to the upstream, the greater the water level fluctuation. The periodic rise or fall of water level under the background of gravity waves in the mainstream will form a tidal flow, which is the driving force for the back-and-forth movement of water bodies in the tributary bays and maintains the continuous water flow oscillation process in the tributary bays.

[0013] Step 3: The high-frequency reciprocating motion of the water body during the oscillation of the water flow is not only accompanied by high-frequency fluctuations in the water level, but also causes the flow velocity to increase or decrease periodically, resulting in intermittent changes in the mixing intensity of the water body, and causing high-frequency fluctuations in the water temperature at locations with large water temperature stratification and temperature gradients. On the one hand, during the oscillation process, part of the energy is gradually dissipated under the action of shear and friction and converted into the internal energy of the water body; on the other hand, it also strengthens the movement of the water body, causing the up and down fluctuations of the interface of the density flow, promoting the vertical mixing of the water body, and thus inhibiting the formation of water temperature stratification.

[0014] Furthermore, the method of using daily reservoir regulation and scheduling to stimulate water flow oscillations to suppress thermal stratification of the reservoir also includes: the water flow oscillation process is accompanied by high-frequency fluctuations in the water level of the tributary bay, the wavelength and period of the water flow oscillation are inherent properties of the tributary bay, and are related to the water depth and length of the bay; and the strength of the water flow oscillation is closely related to the change in the main stream outflow flow; secondly, the mutual superposition or offset of multiple oscillation processes will also increase or reduce the intensity of the water flow oscillation in the bay.

[0015] Furthermore, the energy of the water body's reciprocating motion and the water level amplitude will gradually decay during the water flow oscillation process. However, before the oscillation completely decays, the change in the water level of the main stream causes the next oscillation to be aroused, resulting in a continuous water flow oscillation process in the tributary bay. However, the time interval between the two oscillations determines the intensity of the water flow oscillation in the bay; in comparison, the intraday double-peak regulation can form stronger water flow oscillations than the single-peak regulation.

[0016] Another object of the present invention is to provide a system for suppressing thermal stratification of a reservoir by using the method of suppressing thermal stratification of a reservoir by using daily regulation and scheduling of a reservoir to stimulate water flow oscillation, wherein the system for suppressing thermal stratification of a reservoir by using daily regulation and scheduling of a reservoir to stimulate water flow oscillation comprises: a tributary bay connected to the main stream of the reservoir, and a dam is built on the main stream of the reservoir;

[0017] The water flow oscillation induction module is used to induce gravity waves in the main stream of the reservoir through the daily regulation and dispatching process of the reservoir, and induce high-frequency water flow oscillation phenomena in the tributary bay;

[0018] The reservoir bay water body flow rate control module is used to cause the reservoir bay water level to have high-frequency fluctuation characteristics through the water flow oscillation process, and intermittently increase or decrease the reservoir bay water body flow rate;

[0019] The reservoir thermal stratification suppression module is used to cause intermittent mixing of water bodies through a periodic high-frequency oscillation process, causing high-frequency fluctuations in water temperature, thereby achieving the effect of suppressing water temperature stratification.

[0020] Another object of the present invention is to provide a computer device, which includes a memory and a processor, wherein the memory stores a computer program, and when the computer program is executed by the processor, the processor executes the steps of the method of using daily reservoir regulation and scheduling to stimulate water flow oscillations and suppress thermal stratification of the reservoir.

[0021] Another object of the present invention is to provide a computer-readable storage medium storing a computer program. When the computer program is executed by a processor, the processor executes the steps of the method of using daily reservoir regulation and scheduling to stimulate water flow oscillations and suppress thermal stratification of the reservoir.

[0022] Another object of the present invention is to provide an information data processing terminal, which is used to implement the system that utilizes daily reservoir regulation and scheduling to stimulate water flow oscillations and suppress thermal stratification of the reservoir.

[0023] In combination with the above technical solutions and the technical problems solved, the advantages and positive effects of the technical solutions to be protected by the present invention are as follows:

[0024] First, in view of the technical problems existing in the above-mentioned prior art and the difficulty of solving the problems, the technical solutions to be protected by the present invention and the results and data during the research and development process are closely combined to analyze in detail and deeply how the technical solutions of the present invention solve the technical problems, and some creative technical effects brought about after solving the problems. The specific description is as follows:

[0025] The method provided by the present invention utilizes the daily regulation and scheduling of the reservoir to stimulate water flow oscillation to suppress thermal stratification of the reservoir, and is a method for utilizing water flow oscillation to improve the water temperature stratification of the tributary bay of the river-type reservoir. Water temperature stratification is a natural phenomenon that is common in most lakes and reservoirs, and is often accompanied by phenomena such as dissolved oxygen stratification and water quality stratification. Different lakes and reservoirs have large differences in vertical stratification of water temperature, which are generally divided into three types from strong to weak: stratified type, transitional type and mixed type. Breaking the water temperature stratification is usually an important way to alleviate the lack of oxygen in lake and reservoir water bodies and improve water quality. The present invention proposes to cause gravity waves to form in the main stream of the reservoir through the conventional daily regulation and scheduling process of the reservoir, and induce high-frequency water flow oscillation phenomenon in the tributary bay; the water flow oscillation process not only causes the water level of the bay to have high-frequency fluctuation characteristics, but also intermittently increases or reduces the flow rate of the water body in the bay; this periodic high-frequency oscillation process causes intermittent mixing of the water body, causing high-frequency fluctuations in water temperature, which plays a role in suppressing water temperature stratification to a certain extent. The present invention combines the conventional dispatching of the reservoir and utilizes the special hydrodynamic process of the main stream water level fluctuation inducing the tributary reservoir bay to form a water flow oscillation, forming a natural underwater stirring movement. The method is easy to implement, can significantly improve the hydrodynamic strength of the water body, and inhibit water temperature stratification, which can not only achieve the purpose of improving water quality, but also improve the comprehensive benefits of the reservoir.

[0026] The present invention adjusts the discharge flow of the hydropower station to generate water level fluctuations in front of the dam, triggers gravity waves in the mainstream, and then induces high-frequency water flow oscillation in the tributary bay. The present invention can effectively improve the density stratification characteristics of deep lakes and reservoirs. Compared with the currently commonly used engineering measures such as stratified water intake and water pumping and aeration, it has the advantages of simple operation and obvious effect. Compared with the previous reservoir ecological dispatching, the present invention proposes a new perspective of using the daily regulation and dispatching of the reservoir to improve the water ecological problems caused by the thermal stratification of the reservoir bay through the conventional operation and dispatching of the reservoir. The method provided by the present invention has a significant effect on inhibiting the formation and development of thermal stratification in the tributary bay of the reservoir and improving the water ecology and water environment of the reservoir bay. The present invention combines the daily regulation and dispatching of the reservoir to stimulate the water body in front of the dam to generate gravity waves, which are transmitted upstream to the tributary estuary, inducing a high-frequency water flow oscillation phenomenon in the tributary bay. The method is easy to implement, can affect a wide range of water bodies, significantly increase the mixing intensity of the water body, inhibit water temperature stratification, and achieve the purpose of improving the ecological environment of the water body.

[0027] Second, considering the technical solution as a whole or from the perspective of the product, the technical effects and advantages of the technical solution to be protected by the present invention are described in detail as follows:

[0028] Technical effect: The present invention clarifies the dynamic response mechanism of the reservoir bay hydrodynamics and its water temperature stratification during the daily regulation and scheduling of the reservoir, and provides an ecological scheduling method for improving the thermal stratification characteristics of the reservoir bay of river-type reservoir tributaries by using water flow oscillation. It can significantly increase the mixing intensity of the water body, reduce the temperature difference between the surface and bottom of the reservoir bay water body, inhibit the formation of water temperature stratification, and achieve the purpose of improving the ecological environment of the water body.

[0029] Technical advantages: Based on traditional ecological scheduling, the present invention fully considers the ecological and environmental impact of daily regulation and scheduling, generates a special hydrodynamic phenomenon of water flow oscillation based on the daily peak-shaving scheduling process of the reservoir, improves the hydrodynamic characteristics of tributaries and bays, slows down water temperature stratification, and thus improves the water quality of lakes and reservoirs.

[0030] Third, as auxiliary evidence of the inventiveness of the claims of the present invention, it is also reflected in the following important aspects:

[0031] (1) The expected benefits and commercial value of the technical solution of the present invention after transformation are:

[0032] The present invention utilizes the daily regulation and dispatching of the reservoir to control the hydrodynamic process of the tributary bay, and strengthens the mixing effect of the water body through the high-frequency flow field and water level fluctuation caused by the water flow oscillation, thereby alleviating the water temperature stratification of the lake and reservoir. On the one hand, the weakening of thermal stratification can effectively reduce the risk of algal blooms in the bay in spring and summer, and reduce the salvage costs caused by the outbreak of algal blooms. At the same time, it can also reduce the vertical stratification of the water quality and dissolved oxygen in the bay, reduce the risk of hypoxia and anaerobicity in the bottom water of the bay, improve the water quality of the lake and reservoir, improve the comprehensive utilization efficiency of the water body, efficiently develop and utilize water resources, and promote the harmonious development of people and rivers.

[0033] (2) The technical solution of the present invention fills the technical gap in the industry at home and abroad:

[0034] The present invention fully considers and utilizes the ecological benefits of daily regulation of reservoirs, and for the first time proposes a technical means to use water flow oscillation to break the water temperature stratification of lakes and reservoirs and improve water quality. Compared with previous ecological dispatching, the present invention not only theoretically reveals the response mechanism of the reservoir bay hydrodynamic process to the daily regulation of reservoirs, but also proposes that the intensity of reservoir bay water flow oscillation can be increased by implementing bimodal regulation, which is more conducive to improving the dispatching strategy of lake and reservoir hydrodynamics and water quality processes, and has guiding significance for the water quality management and ecological dispatching implementation of reservoirs with daily regulation capabilities. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments of the present invention. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0036] Figure 1 It is a flow chart of a method for utilizing daily reservoir regulation and scheduling to stimulate water flow oscillation and suppress reservoir thermal stratification provided by an embodiment of the present invention;

[0037] Figure 2 is a schematic diagram of the geographical location of a dam and tributaries provided by an embodiment of the present invention;

[0038] Figure 3 It is a diagram of daily regulation and dispatch of a hydropower station and water level fluctuation process in front of the dam provided by an embodiment of the present invention;

[0039] Figure 4 It is a schematic diagram of the oscillation process (cross-sectional flow velocity) of the water flow in a tributary reservoir provided by an embodiment of the present invention;

[0040] Figure 5 It is a schematic diagram of the water level fluctuation process along the tributary reservoir provided by an embodiment of the present invention;

[0041] Figure 6 It is a diagram of turbulent mixing and high-frequency fluctuation of water temperature in a tributary reservoir provided by an embodiment of the present invention;

[0042] Figure 7 It is a schematic diagram of the dynamic process of water level, flow velocity and water temperature during the oscillation of water flow in a tributary reservoir provided by an embodiment of the present invention;

[0043] Figure 8 It is a schematic diagram of water temperature stratification characteristics of a tributary reservoir provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0044] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0045] In view of the problems existing in the prior art, the present invention provides a method for suppressing thermal stratification of a reservoir by stimulating water flow oscillation through daily reservoir regulation and scheduling. The present invention is described in detail below in conjunction with the accompanying drawings.

[0046] 1. Explanatory Examples In order to enable those skilled in the art to fully understand how to implement the present invention, this section provides an illustrative example that expands and describes the technical solution of the claims.

[0047] like Figure 1 As shown, the method provided by the embodiment of the present invention for using reservoir daily regulation and scheduling to stimulate water flow oscillation and suppress reservoir thermal stratification includes the following steps:

[0048] S101, through the daily regulation and dispatching process of the reservoir, gravity waves are formed in the main stream of the reservoir, and high-frequency water flow oscillations are induced in the tributary bays;

[0049] S102, through the process of water flow oscillation, the water level of the reservoir bay has a high-frequency fluctuation characteristic, intermittently increasing or decreasing the flow velocity of the reservoir bay water body;

[0050] S103, through the periodic high-frequency oscillation process, the water body is intermittently mixed, causing high-frequency fluctuations in water temperature, thereby achieving the effect of suppressing water temperature stratification.

[0051] As a preferred embodiment, the method for suppressing thermal stratification of a reservoir by using daily reservoir regulation and scheduling to stimulate water flow oscillation provided in the embodiment of the present invention includes a tributary bay connected to the main stream of the reservoir, and a dam is built on the main stream of the reservoir, specifically including the following steps:

[0052] (1) In river-type reservoirs, the daily regulation characteristics of the outflow of the hydropower station are used. When the outflow suddenly increases or decreases, the water level in front of the dam is stimulated to rise or fall, forming gravity waves that propagate to the upstream of the reservoir, causing a phenomenon similar to false tides to form at the mouth of the main and tributary reservoirs;

[0053] (ii) The water level fluctuations at the estuaries of the main and tributary rivers form tidal flow, which drives the water level fluctuations in the tributary bays and forms high-frequency water flow oscillations. Its characteristics also include:

[0054] (3) The oscillation of water flow is accompanied by high-frequency fluctuations in the water level of the tributary bay. The wavelength and period of the oscillation are inherent properties of the tributary bay and are related to the water depth and length of the bay.

[0055] (iv) During the oscillation process, the water velocity in the reservoir bay has a high-frequency fluctuation characteristic; the water flow oscillation can cause intermittent turbulence in the boundary layer, causing high-frequency fluctuations in water temperature, and by promoting full mixing of the upper and lower water bodies, it plays a role in slowing down the water temperature stratification.

[0056] The embodiment of the present invention utilizes the generation and transmission mechanism of surface gravity waves, combined with the daily regulation and dispatch of the reservoir, to stimulate high-frequency water flow oscillations in the tributary bay. During the water flow oscillation process, accompanied by high-frequency water level fluctuations, the closer to the end of the bay, the greater the water level fluctuation amplitude, and at the same time, the flow velocity of the bay water body will intermittently increase or decrease, forming an intermittent mixing effect, causing high-frequency fluctuations in water temperature, thereby slowing down the water temperature stratification in the bay, affecting the transport of substances in the water body, and playing a role in improving water quality.

[0057] The embodiment of the present invention utilizes the daily regulation and scheduling of the reservoir, and can stimulate the gravity wave of the main stream and form water flow oscillation in the tributary bay when the outflow flow suddenly increases or decreases. The formation of the water flow oscillation provided by the embodiment of the present invention has no necessary relationship with whether the tributary bay has water temperature stratification. The physical characteristics of the water flow oscillation, such as the period and wavelength of the oscillation, are the inherent properties of the tributary bay, and are related to the water depth and length of the bay; and the strength of the water flow oscillation is closely related to the change in the outflow flow of the main stream.

[0058] The embodiment of the present invention combines the daily regulation and dispatching of the reservoir to stimulate the water body in front of the dam to generate gravity waves, which are transmitted upstream to the tributary estuary, inducing a high-frequency water flow oscillation phenomenon in the tributary bay. The method for suppressing thermal stratification of the reservoir provided by the embodiment of the present invention is easy to implement, can affect a large range of water bodies, significantly increase the mixing intensity of the water body, suppress water temperature stratification, and achieve the purpose of improving the ecological environment of the water body.

[0059] 2. Application Examples: In order to prove the creativity and technical value of the technical solution of the present invention, this section provides application examples of the technical solution of the claims on specific products or related technologies.

[0060] Taking the Xiangxi River Bay of the Three Gorges Reservoir as an example, this paper carried out high-frequency monitoring of water flow and water level from May 6 to May 13, 2020, and analyzed the water flow oscillation characteristics of the tributary bay under the single-peak daily regulation process during this period and its impact on water mixing and water temperature stratification, as follows Figure 2-6To further clarify the effect of different daily regulation and dispatching processes on the improvement of tributary reservoir water temperature stratification, three daily regulation modes of single peak, double peak, and no peak were designed through numerical simulation experiments. The daily water level fluctuation of the single peak and double peak daily regulation processes was set to 1m, and the dispatching conditions were designed as follows: Figure 7 As shown in Figure 2, the water temperature stratification process of the tributary reservoir under different dispatching conditions is as follows: Figure 8 The simulation experiment shows that the implementation of single-peak and double-peak daily regulation can effectively improve the water temperature stratification of tributary reservoirs. In comparison, the effect of double-peak regulation is more significant.

[0061] 3. Evidence of the effects of the embodiments. The embodiments of the present invention have achieved some positive effects during the development or use process, and indeed have great advantages over the prior art. The following content is described in conjunction with the data, charts, etc. of the test process.

[0062] The embodiment of the present invention provides a method for improving the thermal stratification characteristics of a tributary bay of a river-type reservoir by using water flow oscillation. The geographical location of the dam and the tributary is shown in the figure below. Figure 2 As shown, the reservoir tributary b connected to the reservoir main stream a, the reservoir tributary, specifically includes the following steps:

[0063] (I) In river-type reservoirs, the daily regulation process of the outflow of the hydropower station is used. The increase or decrease of the outflow within a day causes the water level in front of the dam to change periodically. The daily fluctuation amplitude of the water level can reach 0.4m. Figure 3 The water level fluctuation in front of the dam propagates to the upstream of the mainstream in the form of gravity waves, forming a phenomenon similar to false tides at the estuaries of the mainstream and tributaries, thereby causing water flow oscillation in the tributary bay b, as shown in Figure 4 As shown in the figure, the water flow oscillation caused the periodic fluctuation of the flow velocity of the entire profile, with a fluctuation period of 1.8 hours.

[0064] (ii) High-frequency flow oscillations in the reservoir tributaries are accompanied by high-frequency fluctuations in water levels, such as Figure 5 As shown in the figure, the amplitude of high-frequency water level fluctuation is about 0.1m, and the period is 1.8 hours. Affected by the narrowing of the river channel, the amplitude of water level fluctuation is larger as it approaches the upper reaches of the reservoir bay;

[0065] (III) The oscillation of water flow causes intermittent mixing of water bodies, and the turbulent kinetic energy, turbulent kinetic energy dissipation rate, and water temperature all change periodically. The change cycle is consistent with the water level and flow rate cycle, such as Figure 6 As shown in the figure, during the oscillation process, the oscillation intensifies, the water velocity increases, the turbulent mixing intensifies, the water stratification weakens, and the oscillation causes intermittent changes in the water temperature stratification.

[0066] (IV) In order to further compare the impact of different daily regulation processes on the water temperature stratification of tributary reservoirs, three different dispatching conditions (single peak, double peak and no regulation) were designed through numerical models. Figure 7 As shown in Figure 2, the water temperature stratification characteristics of the tributary reservoir are as follows: Figure 8 By comparing different regulation methods, it is found that both single-peak and double-peak regulation can stimulate the oscillation of water flow in the tributary bay, causing high-frequency fluctuations in water temperature and weakening the stratification of water temperature in the bay. In comparison, the effect of double-peak regulation is more significant.

[0067] (V) The characteristics of water flow oscillation are the inherent properties of the tributary bay. For example, the water level changes and periods caused by the oscillations are related to the length and water depth of the bay, while the strength of the oscillations is related to the driving force of the mainstream, that is, the intensity of gravity waves caused by a sudden increase or decrease in reservoir outflow.

[0068] The embodiment of the present invention adjusts the discharge flow of the hydropower station to generate water level fluctuations in front of the dam, triggering gravity waves in the main stream, and further inducing high-frequency water flow oscillations in the tributary bay. The embodiment of the present invention can effectively improve the density stratification characteristics of deep-water lakes and reservoirs. Compared with the currently commonly used engineering measures such as stratified water intake and water pumping and aeration, it has the advantages of simple operation and obvious effect. Compared with the previous reservoir ecological scheduling, the embodiment of the present invention proposes a new perspective of utilizing the daily regulation and scheduling of reservoirs to improve the water ecological problems caused by thermal stratification in the reservoir bay through the regular operation and scheduling of the reservoir. The method provided by the embodiment of the present invention has a significant effect on inhibiting the formation and development of thermal stratification in the reservoir bay of the reservoir tributary, and improving the water ecology and water environment of the reservoir bay.

[0069] It should be noted that the embodiments of the present invention can be implemented by hardware, software, or a combination of software and hardware. The hardware part can be implemented using dedicated logic; the software part can be stored in a memory and executed by an appropriate instruction execution system, such as a microprocessor or dedicated design hardware. It can be understood by a person of ordinary skill in the art that the above-mentioned devices and methods can be implemented using computer executable instructions and / or contained in a processor control code, such as a carrier medium such as a disk, CD or DVD-ROM, a programmable memory such as a read-only memory (firmware), or a data carrier such as an optical or electronic signal carrier. Such code is provided on the carrier medium. The device and its modules of the present invention can be implemented by hardware circuits such as very large-scale integrated circuits or gate arrays, semiconductors such as logic chips, transistors, etc., or programmable hardware devices such as field programmable gate arrays, programmable logic devices, etc., can also be implemented by software executed by various types of processors, and can also be implemented by a combination of the above-mentioned hardware circuits and software, such as firmware.

[0070] The above description is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Any modifications, equivalent substitutions and improvements made by any technician familiar with the technical field within the technical scope disclosed by the present invention and within the spirit and principle of the present invention should be covered by the protection scope of the present invention.

Claims

1. A method for suppressing thermal stratification of a reservoir by stimulating water flow oscillation through daily reservoir regulation, characterized in that: The method of using daily reservoir regulation to stimulate water flow oscillation and suppress reservoir thermal stratification includes: suddenly increasing or reducing the discharge flow of the hydropower station to generate water level fluctuations in front of the dam, triggering mainstream gravity waves, inducing high-frequency water flow oscillations in the tributary bay, and thus achieving the suppression of reservoir thermal stratification; The method of using daily regulation and scheduling of reservoirs to stimulate water flow oscillations and suppress thermal stratification of reservoirs also includes: using the generation and transmission mechanism of surface gravity waves, combined with the daily regulation and scheduling of reservoirs, to stimulate high-frequency water flow oscillations in the tributary bay; during the water flow oscillation process, accompanied by high-frequency water level fluctuations, the closer to the end of the bay, the greater the water level fluctuation amplitude, and at the same time, the flow velocity of the water body in the bay is intermittently increased or decreased, causing high-frequency fluctuations in water temperature, forming intermittent mixing enhancement, and thus slowing down the water temperature stratification in the bay; The method of using daily reservoir regulation to stimulate water flow oscillation and suppress reservoir thermal stratification also includes: using the daily regulation characteristics of the outflow of the hydropower station in the river channel reservoir, when the outflow suddenly increases or decreases, the water level in front of the dam is stimulated to rise or fall, forming gravity waves and propagating upstream of the reservoir, causing a phenomenon similar to false tides to form at the mouths of the main and tributary bays; the water level fluctuations at the mouths of the main and tributary bays form tidal throughput, driving the water level fluctuations of the tributary bays and forming high-frequency water flow oscillations; The water flow oscillation process is accompanied by high-frequency fluctuations in the water level of the tributary bay. The wavelength and period of the water flow oscillation are inherent properties of the tributary bay, and are related to the water depth and length of the bay. The strength of the water flow oscillation is closely related to the change in the outflow flow of the main stream.

2. The method for suppressing thermal stratification of a reservoir by stimulating water flow oscillation by daily reservoir regulation and scheduling as claimed in claim 1, characterized in that: During the oscillation process, the velocity of the reservoir bay current has a high-frequency fluctuation characteristic; Water flow oscillation can cause intermittent turbulence in the boundary layer, causing high-frequency fluctuations in water temperature, and by promoting sufficient mixing of the upper and lower water bodies, it can slow down the water temperature stratification.

3. A system for suppressing thermal stratification of a reservoir by using the method of suppressing thermal stratification of a reservoir by using daily regulation and scheduling of a reservoir to stimulate water flow oscillation, characterized in that: The system for using daily reservoir regulation to stimulate water flow oscillation and suppress reservoir thermal stratification comprises: a tributary bay connected to the main stream of the reservoir, and a dam is built on the main stream of the reservoir; The water flow oscillation induction module is used to induce gravity waves in the main stream of the reservoir through the daily regulation and dispatching process of the reservoir, and induce high-frequency water flow oscillation phenomena in the tributary bay; The water velocity control module of the reservoir bay is used to cause the water level of the reservoir bay to have high-frequency fluctuation characteristics through the water flow oscillation process, and to intermittently increase or decrease the water velocity of the reservoir bay; The reservoir thermal stratification suppression module is used to cause intermittent mixing of water bodies through a periodic high-frequency oscillation process, causing high-frequency fluctuations in water temperature, thereby achieving the effect of suppressing water temperature stratification.

4. A computer device, characterized in that: The computer device includes a memory and a processor, the memory stores a computer program, and when the computer program is executed by the processor, the processor executes the steps of the method for suppressing thermal stratification of a reservoir by using daily reservoir regulation and scheduling to stimulate water flow oscillations as described in any one of claims 1 to 2.

5. A computer-readable storage medium storing a computer program, wherein when the computer program is executed by a processor, the processor executes the steps of the method for suppressing thermal stratification of a reservoir by stimulating water flow oscillations through daily reservoir regulation and scheduling as described in any one of claims 1 to 2.

6. An information data processing terminal, characterized in that: The information data processing terminal is used to implement the system for utilizing daily reservoir regulation and scheduling to stimulate water flow oscillation and suppress thermal stratification of the reservoir as described in claim 3.

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