Urban musical fountain design study

Urban musical fountain design study

Coordinating stage design, hydraulics, light, sound and operation

A musical fountain becomes a lasting experience when the movement of water, the change of light and the structure of the music are related to each other. This coordination begins at the stage of equipment selection: the arrangement of nozzles, the number of independent groups, the response speed of the pumps and the position of the spectators all affect the final show.

In this chapter, a hypothetical project is examined to illustrate the design process. Dimensions, flow rates, capacities and response times are educational assumptions and are not considered specifications of a given GSO project or product. The goal is to clarify the relationship between decisions and calculations; The executive selection of equipment requires real project information.

44–1. Defining the mission of the project

For the present example, a pond fountain in the public space adjacent to a cultural and commercial complex is considered. Spectators watch the show from outside the pond, and public access to the water is not part of the plan's use.

The mission of the project is defined in three situations:

• Musical show: performing timed programs with water, light and sound.

• Everyday mode: smooth movement of water between performances, with less energy consumption.

• Restricted mode: program execution according to wind or operating constraints.

These conditions should be written from the beginning in the service description. If the equipment is selected only for the highest spray height, it may not have the desired quality or stable performance at rest.

The success of the project should also be defined by verifiable criteria: proper visibility of the audience, repeatability of the show, accessibility, repairability, and the possibility of managing the collection with the available human resources and budget.

44–2. Sample specifications and scene placement

The inserted depth is only an input for the volume calculation and is not considered as a measure of pond safety.

In primary placement, the central group is used for main emphasis and the six peripheral groups are used to create sequential movement, symmetry, and bilateral responses. The main viewing angle of the audience must be determined before fixing this arrangement; A composition that is legible from the front may be seen as compressed from the sides.

Figure note from the source manuscript

Figure 44-1: conceptual plan of the fountain scene

24 x 8 m pond, six peripheral groups with identifiers G1 to G6 and central group G7 are displayed. The main viewing area, public passageway, location of loudspeakers and maintenance access should also be specified. Subtitle: "Educational placement; The spacing of the nozzles and the viewing area should be finalized with a spray test and visibility check.

44–3. Transforming the demonstration idea into equipment capability

In this example, four nozzles of each group change height with a common command. Therefore, the system has seven independent units of water movement, although it has 28 nozzles.

This difference should be clear in the purchase documents:

The number of nozzles is not the same as the number of independent programmable points.

If the employer wants each nozzle to turn on and off independently, another arrangement of valves, pumps and controls will be needed.

For example, Fontana introduced the YSwitch to provide independent control of outputs in a shared pump arrangement. This capability must be checked in the same hydraulic assembly selected and cannot be automatically extended to any valve or network. Introducing YSwitch from Fontana ^[295]

Control nozzles, variable speed pumps and control equipment have also been introduced on the GSO website. The selection for the project should be based on the performance curve and connection map of the proposed model. GSO urban fountain products ^[296]

44–4. Calculation of the flow rate of spraying groups

The assumed flow rate of each peripheral nozzle is 1.2 cubic meters per hour:

$Q_{outer,group}=4\times 1.2=4.8m^3/h$

Dubai six peripheral groups:

$Q_{outer,total}=6\times 4.8=28.8m^3/h$

For each central nozzle, a flow rate of three cubic meters per hour is assumed:

$Q_{center}=4\times 3=12m^3/h$

In the simultaneous activity of all groups:

$Q_{display,max}=28.8+12=40.8m^3/h$

The unit of flow rate is cubic meters per hour.

This value is the circulating current of the display. After spraying, the water returns to the pond; Therefore, 40.8 cubic meters per hour is not the fresh water consumption of the project.

44–5. Arrangement of water circuit and initial volume

In the conceptual arrangement of this example, each group has its own pump. Water is taken from the pool, passes through the circuit of the same group and returns to the pool after exiting the nozzles.

The filter circuit is provided independently so that its program does not depend on the brightness of the display. Details of water harvesting, protection of inlets, mixing and prevention of low circulation areas are determined in the detailed design.

Geometric volume of pond water:

$V_{basin}=24\times 8\times 0.45=86.4m^3$

To calculate the total inventory, the water volume of the pipes, filters and any side tanks should be added. The volume of 86.4 cubic meters alone is not the final basis for selecting the treatment.

A show fountain also needs a water quality management plan. CDC emphasizes the role of sediment, biofilm, temperature, water retention, and residual disinfectant in controlling Legionella in decorative fountains. CDC Guidelines for Decorative Fountains ^[297]

44–6. Estimating the power of display pumps

To continue the example, the total head of each peripheral group is assumed to be 14 meters and the total head of the central group is assumed to be 24 meters. These heads should be obtained in the actual project from the sum of the necessary nozzle pressure, level difference and path drop; The pump head is not the same as the visible height of the fountain.

The input power can be estimated as follows:

$P_{electric}=\frac{\rho gQH}{{\eta }_{overall}}$

In this regard, the total efficiency includes the pump, motor and drive.

For a peripheral group, with an assumed total return of 0.55:

$P_{outer,group}=\frac{1000\times 9.81\times (4.8/3600)\times 14}{0.55}\approx 333W$

Power of six groups:

$P_{outer,total}\approx 6\times 0.333=2.00kW$

For the central group, with an assumed total return of 0.60:

$P_{center}=\frac{1000\times 9.81\times (12/3600)\times 24}{0.60}\approx 1.31kW$

Therefore:

$P_{display,max}\approx 3.31kW$

This number is the estimation of the input power at the hypothetical working points. The rated power of the engine, the permissible working range, the suction conditions and the performance at different speeds must still be controlled with the actual curve of the equipment.

44–7. Height change and pump response limit

In the conditions of appropriate similarity for a pump with a fixed impeller diameter, the following approximate relationships are established:

$Q\propto nH\propto n^{2}P\propto n^3$

KSB explains these relationships with similarity and yield assumptions and constraints. Pump similarity rules from KSB ^[298]

For a turn ratio of 0.8, the theoretical head and power ratios will be 0.64 and 0.512, respectively. However, the actual operating point shift also depends on the network curve and efficiency; These ratios do not directly determine the percentage of energy savings of the entire fountain.

In planning the show, the ramp up and down times should be coordinated with the actual response of the group. If the music has 120 beats per minute, the beat interval is equal to:

$t_{beat}=\frac{60}{120}=0.5s$

A group that takes more than one second to reach a target state cannot switch between two stable states every half second. In such a section, water changes can be set on longer musical phrases and shorter accents can be left to the light.

44–8. Water, light and sound delay compensation

Sending commands at the same time does not necessarily lead to seeing the result at the same time. The response of water, lighting and sound chain should be measured.

For a hypothetical event, we consider the following delays at the viewing reference point:

If the optimal time to receive all three events is 60 seconds:

$t_{command}=t_{target}-\tau$

So the corresponding times are:

• Water command: 58.90 seconds;

• Light command: 59.96 seconds;

• Voice command or corresponding position: 59.92 seconds.

In continuous music playback, audio tuning is usually done by aligning the timeline and delaying the entire track; It is not necessary to run a separate audio file for each beat.

The water delay is also not the same for all changes. Moving from off to high altitude may differ from changing between two nearby altitudes. Each group's response table must be completed at setup.

Figure note from the source manuscript

Figure 2–44: A timing diagram of an event

Three rows of water, light and sound are displayed with the time of sending the command and a common vertical line at 60 seconds. Subtitle: "Numbers are fictitious; "The final timing will be adjusted based on on-site measurements."

44–9. Designing the structure of a twelve-minute show

For this study, the following basic structure is proposed:

This table is the compilation framework. The length of the sections should be adapted to the chosen music.

In the first version, it is better for each section to have a recognizable visual idea. All lights on and constant activity of all nozzles limit the possibility of making a difference between the low and peak sections.

Systems such as OASE's WECS III provide coordination of fountain equipment and receive status information via DMX/RDM. The existence of such tools does not eliminate the need for artistic editing and on-site adjustment. Introducing the fountain control from OASE ^[299]

44–10. Lighting and electric load estimation

Assuming 28 24 watt lights:

$P_{LED,DC}=28\times 24=672W$

If the power supply efficiency is 90%:

$P_{lighting,AC}=\frac{672}{0.90}\approx 747W$

In case of direct 24 V power supply, the theoretical sum of the output current of the sources:

$I_{DC,total}=\frac{672}{24}=28A$

This number is not the current of a single cable. Division of circuits, path length, voltage drop and protection of each branch must be calculated separately.

For the initial estimate of simultaneous load, we add the following assumptions:

This total is not the final capacity of the branch or panel. Actual equipment rated current, power factor, drive behavior, starting conditions, and side loads must be considered in electrical design.

44–11. Sound design for viewing range

The goal of the sound design is for the music to be heard clearly within the audience with controlled disturbance to the surroundings.

For this example, the evaluation points include the center of the viewing area, its two ends, and the nearest sensitive user. The selection of the number and direction of the speakers should be done with the actual geometry of the space.

The rated power of a speaker or amplifier alone does not indicate sound coverage. In the delivery of the project, coverage uniformity, clarity, delay and sound level should be measured at designated points. Acceptance limits should also be recorded in the project specification before purchasing the equipment.

If the audience is placed at very different distances, the perceived synchronicity of water and sound will not be the same for everyone. The final setting should be based on the original viewing range.

44–12. Bad and alternate versions of the show

The wind can change the shape of the fountain, the landing place of the water and the quality of the lighting. Step-by-step height reduction or automatic stop is also provided in OASE's wind control equipment. OASE wind dependent control ^[300]

For the sample project, three versions are defined:

Numerical wind thresholds should be determined by wind direction, nozzle-to-edge distance, spray type, and site testing.

The return from limited to full mode should also have a delay and an appropriate distance between the entry and exit threshold so that the wind fluctuation does not cause frequent changes in the situation. In the absence of valid wind data, the controller must have a predefined response.

44–13. Daily energy calculation

Eight twelve-minute shows make up the following daily run times:

$t_{show}=8\times \frac{12}{60}=1.6h/day$

For the energy budget example, we assume the following values:

The twelve-hour purification time is only an assumption for energy calculation; The actual duration of work should be determined from the water management plan. If the same auxiliary load is active 24 hours, the daily energy of the table increases by 14.4 kWh.

Average powers should also be corrected by measurement after start-up. Determining the annual consumption based on the nominal power of the engine and the number of shows is not enough alone.

Figure note from the source manuscript

Figure 3-44: Daily energy chart

Draw a bar graph with the share of the six rows of the above table. Title: "Energy budget based on educational assumptions". Display time consumption and non-display time consumption are shown with distinguishable colors.

44–14. Control logic and error behavior

Project control should have three specific tasks:

• Implementation of artistic schedule;

• Checking equipment readiness and operating conditions;

• Implementation of necessary protections and stops.

The show command is executed only in authorized conditions. For example, a drop in water level, a pump error, or an invalid sensor must not be ignored by continuing the music file.

In the failure of a peripheral group, a limited version of the pre-tested can be defined. In case of failure of the central group, it should also be clear that the show will stop or have an alternative version.

Retaining the last command value after disconnection is not suitable for all equipment. The status of each output during data interruption, power interruption and power return should be recorded in the cause and effect table. The show should not be restarted unintentionally after the power is restored without checking readiness.

44–15. Delivery test and artistic arrangement

The delivery of the musical fountain should cover the technical test and set-up of the show.

The test of the groups should be done separately and in combination. Also, the acceptance of simultaneity must rely on specific time points and observation locations; Statements such as "fully aligned" do not provide a clear basis for delivery without a measurement method.

Figure note from the source manuscript

Figure 44-4: Documentary of the night setup from the company's archives

Select a general view of the test run and an image of the operator setting up the program. The subtitle should include the name of the actual project, the work phase and the subject of the test. The image should not be presented as a hypothetical project implementation of this chapter.

44–16. Final documents and developability

The main results of this study are:

The delivery file should include as-built drawings, equipment specifications, final settings, group response table, back-up programs and operating instructions. Editable display files, software licenses, and limits on the employer's authority to change or add to the program should also be clear in the contract.

For future development, the control capacity, board space and the possibility of adding effects should be considered along with the electrical, hydraulic capacity and installation location. Adding a few software outputs alone doesn't mean the fountain is ready for more gear.

The long-term value of this project will depend on the ability to regularly execute, maintain and update its content. The design should make it possible for the complex to continue to be operated with predictable quality after changing seasons, cultural programs or client needs.